Remove output redirect from corpus test runner.

The corpus tests redirect output to a string but they just output it
later anyway. This CL removes the output redirect and removes the
redirect_output flag which will always be False now.

Review-Url: https://codereview.chromium.org/1927633002
diff --git a/testing/tools/common.py b/testing/tools/common.py
index 6e9de7c..1e1d257 100755
--- a/testing/tools/common.py
+++ b/testing/tools/common.py
@@ -18,12 +18,9 @@
   raise Exception('Confused, can not determine OS, aborting.')
 
 
-def RunCommand(cmd, redirect_output=False):
+def RunCommand(cmd):
   try:
-    if redirect_output:
-      sys.stdout.write(subprocess.check_output(cmd, stderr=subprocess.STDOUT))
-    else:
-      subprocess.check_call(cmd)
+    subprocess.check_call(cmd)
     return None
   except subprocess.CalledProcessError as e:
     return e