bpo-35214: MSan workarounds for socket, time, and test_faulthandler. (GH-11375) (GH-11378)

Add Clang Memory Sanitizer build instrumentation to work around
false positives from the socket and time modules as well as skipping
a couple test_faulthandler tests.
(cherry picked from commit b474e6774d60fa67d5373e361a0ed53c18b24f53)

Co-authored-by: Gregory P. Smith <greg@krypto.org>
diff --git a/Lib/test/test_faulthandler.py b/Lib/test/test_faulthandler.py
index d6dc4ba..984690f 100644
--- a/Lib/test/test_faulthandler.py
+++ b/Lib/test/test_faulthandler.py
@@ -5,6 +5,7 @@
 import signal
 import subprocess
 import sys
+import sysconfig
 from test import support
 from test.support import script_helper, is_android
 import tempfile
@@ -19,6 +20,10 @@
 
 TIMEOUT = 0.5
 MS_WINDOWS = (os.name == 'nt')
+MEMORY_SANITIZER = (
+    sysconfig.get_config_var("CONFIG_ARGS") and
+    ("--with-memory-sanitizer" in sysconfig.get_config_var("CONFIG_ARGS"))
+)
 
 def expected_traceback(lineno1, lineno2, header, min_count=1):
     regex = header
@@ -252,6 +257,8 @@
             3,
             'Segmentation fault')
 
+    @unittest.skipIf(MEMORY_SANITIZER,
+                     "memory-sanizer builds change crashing process output.")
     @skip_segfault_on_android
     def test_enable_file(self):
         with temporary_filename() as filename:
@@ -267,6 +274,8 @@
 
     @unittest.skipIf(sys.platform == "win32",
                      "subprocess doesn't support pass_fds on Windows")
+    @unittest.skipIf(MEMORY_SANITIZER,
+                     "memory-sanizer builds change crashing process output.")
     @skip_segfault_on_android
     def test_enable_fd(self):
         with tempfile.TemporaryFile('wb+') as fp: