Upgrade yapf to 0.20.0

Upgrade yapf version to 0.20.0 and reformat Python files.
diff --git a/tools/run_tests/python_utils/dockerjob.py b/tools/run_tests/python_utils/dockerjob.py
index d2941c0..2d22dc1 100755
--- a/tools/run_tests/python_utils/dockerjob.py
+++ b/tools/run_tests/python_utils/dockerjob.py
@@ -50,8 +50,8 @@
             return int(output.split(':', 2)[1])
         except subprocess.CalledProcessError as e:
             pass
-    raise Exception('Failed to get exposed port %s for container %s.' %
-                    (port, cid))
+    raise Exception('Failed to get exposed port %s for container %s.' % (port,
+                                                                         cid))
 
 
 def wait_for_healthy(cid, shortname, timeout_seconds):
diff --git a/tools/run_tests/python_utils/filter_pull_request_tests.py b/tools/run_tests/python_utils/filter_pull_request_tests.py
index 8e0dc70..4c09b34 100644
--- a/tools/run_tests/python_utils/filter_pull_request_tests.py
+++ b/tools/run_tests/python_utils/filter_pull_request_tests.py
@@ -124,10 +124,10 @@
   """
     # Get file changes between branch and merge-base of specified branch
     # Not combined to be Windows friendly
-    base_commit = check_output(
-        ["git", "merge-base", base_branch, "HEAD"]).rstrip()
-    return check_output(
-        ["git", "diff", base_commit, "--name-only", "HEAD"]).splitlines()
+    base_commit = check_output(["git", "merge-base", base_branch,
+                                "HEAD"]).rstrip()
+    return check_output(["git", "diff", base_commit, "--name-only",
+                         "HEAD"]).splitlines()
 
 
 def _can_skip_tests(file_names, triggers):
diff --git a/tools/run_tests/python_utils/jobset.py b/tools/run_tests/python_utils/jobset.py
index 454d09b..6a33913 100755
--- a/tools/run_tests/python_utils/jobset.py
+++ b/tools/run_tests/python_utils/jobset.py
@@ -133,12 +133,13 @@
                     logging.info(explanatory_text)
                 logging.info('%s: %s', tag, msg)
             else:
-                sys.stdout.write('%s%s%s\x1b[%d;%dm%s\x1b[0m: %s%s' % (
-                    _BEGINNING_OF_LINE, _CLEAR_LINE, '\n%s' % explanatory_text
-                    if explanatory_text is not None else '',
-                    _COLORS[_TAG_COLOR[tag]][1], _COLORS[_TAG_COLOR[tag]][0],
-                    tag, msg, '\n'
-                    if do_newline or explanatory_text is not None else ''))
+                sys.stdout.write(
+                    '%s%s%s\x1b[%d;%dm%s\x1b[0m: %s%s' %
+                    (_BEGINNING_OF_LINE, _CLEAR_LINE, '\n%s' % explanatory_text
+                     if explanatory_text is not None else '',
+                     _COLORS[_TAG_COLOR[tag]][1], _COLORS[_TAG_COLOR[tag]][0],
+                     tag, msg, '\n'
+                     if do_newline or explanatory_text is not None else ''))
             sys.stdout.flush()
             return
         except IOError, e:
@@ -210,8 +211,8 @@
 
     def __str__(self):
         return '%s: %s %s' % (self.shortname, ' '.join(
-            '%s=%s' % kv
-            for kv in self.environ.items()), ' '.join(self.cmdline))
+            '%s=%s' % kv for kv in self.environ.items()),
+                              ' '.join(self.cmdline))
 
 
 class JobResult(object):
@@ -284,8 +285,9 @@
                 self._process = try_start()
                 break
             except OSError:
-                message('WARNING', 'Failed to start %s, retrying in %f seconds'
-                        % (self._spec.shortname, delay))
+                message('WARNING',
+                        'Failed to start %s, retrying in %f seconds' %
+                        (self._spec.shortname, delay))
                 time.sleep(delay)
                 delay *= 2
         else:
@@ -343,8 +345,8 @@
                     if real > 0.5:
                         cores = (user + sys) / real
                         self.result.cpu_measured = float('%.01f' % cores)
-                        self.result.cpu_estimated = float('%.01f' %
-                                                          self._spec.cpu_cost)
+                        self.result.cpu_estimated = float(
+                            '%.01f' % self._spec.cpu_cost)
                         measurement = '; cpu_cost=%.01f; estimated=%.01f' % (
                             self.result.cpu_measured, self.result.cpu_estimated)
                 if not self._quiet_success:
@@ -378,8 +380,8 @@
             else:
                 message(
                     'TIMEOUT',
-                    '%s [pid=%d, time=%.1fsec]' %
-                    (self._spec.shortname, self._process.pid, elapsed),
+                    '%s [pid=%d, time=%.1fsec]' % (self._spec.shortname,
+                                                   self._process.pid, elapsed),
                     stdout(),
                     do_newline=True)
                 self.kill()
diff --git a/tools/run_tests/python_utils/start_port_server.py b/tools/run_tests/python_utils/start_port_server.py
index 5572cdc..37995ac 100644
--- a/tools/run_tests/python_utils/start_port_server.py
+++ b/tools/run_tests/python_utils/start_port_server.py
@@ -43,16 +43,16 @@
     if running:
         current_version = int(
             subprocess.check_output([
-                sys.executable, os.path.abspath(
-                    'tools/run_tests/python_utils/port_server.py'),
+                sys.executable,
+                os.path.abspath('tools/run_tests/python_utils/port_server.py'),
                 'dump_version'
             ]))
         logging.info('my port server is version %d', current_version)
         running = (version >= current_version)
         if not running:
             logging.info('port_server version mismatch: killing the old one')
-            urllib.urlopen('http://localhost:%d/quitquitquit' %
-                           _PORT_SERVER_PORT).read()
+            urllib.urlopen(
+                'http://localhost:%d/quitquitquit' % _PORT_SERVER_PORT).read()
             time.sleep(1)
     if not running:
         fd, logfile = tempfile.mkstemp()
@@ -61,7 +61,8 @@
         args = [
             sys.executable,
             os.path.abspath('tools/run_tests/python_utils/port_server.py'),
-            '-p', '%d' % _PORT_SERVER_PORT, '-l', logfile
+            '-p',
+            '%d' % _PORT_SERVER_PORT, '-l', logfile
         ]
         env = dict(os.environ)
         env['BUILD_ID'] = 'pleaseDontKillMeJenkins'
@@ -91,8 +92,8 @@
                 # try one final time: maybe another build managed to start one
                 time.sleep(1)
                 try:
-                    urllib.urlopen('http://localhost:%d/get' %
-                                   _PORT_SERVER_PORT).read()
+                    urllib.urlopen(
+                        'http://localhost:%d/get' % _PORT_SERVER_PORT).read()
                     logging.info(
                         'last ditch attempt to contact port server succeeded')
                     break