Only pass -E to the child interpreter if our interpreter was running in that

mode.  Explicitly remove the PYTHONFAULTHANDLER environment variable before
launching a child interpreter when its presence would impact the test (the
reason -E was being used in the first place).

This enables running the test in an environment where other Python environment
variables must be set in order for things to run (such as using PYTHONHOME to
tell an embedded interpreter where it should think it lives).

Lib/test/test_faulthandler.py

@@ -250,17 +250,25 @@ class FaultHandlerTests(unittest.TestCase):
     def test_disabled_by_default(self):
         # By default, the module should be disabled
         code = "import faulthandler; print(faulthandler.is_enabled())"
-        args = (sys.executable, '-E', '-c', code)
-        # don't use assert_python_ok() because it always enable faulthandler
-        output = subprocess.check_output(args)
+        args = filter(None, (sys.executable,
+                             "-E" if sys.flags.ignore_environment else "",
+                             "-c", code))
+        env = os.environ.copy()
+        env.pop("PYTHONFAULTHANDLER", None)
+        # don't use assert_python_ok() because it always enables faulthandler
+        output = subprocess.check_output(args, env=env)
         self.assertEqual(output.rstrip(), b"False")
 
     def test_sys_xoptions(self):
         # Test python -X faulthandler
         code = "import faulthandler; print(faulthandler.is_enabled())"
-        args = (sys.executable, "-E", "-X", "faulthandler", "-c", code)
-        # don't use assert_python_ok() because it always enable faulthandler
-        output = subprocess.check_output(args)
+        args = filter(None, (sys.executable,
+                             "-E" if sys.flags.ignore_environment else "",
+                             "-X", "faulthandler", "-c", code))
+        env = os.environ.copy()
+        env.pop("PYTHONFAULTHANDLER", None)
+        # don't use assert_python_ok() because it always enables faulthandler
+        output = subprocess.check_output(args, env=env)
         self.assertEqual(output.rstrip(), b"True")
 
     def test_env_var(self):
@@ -269,7 +277,7 @@ class FaultHandlerTests(unittest.TestCase):
         args = (sys.executable, "-c", code)
         env = os.environ.copy()
         env['PYTHONFAULTHANDLER'] = ''
-        # don't use assert_python_ok() because it always enable faulthandler
+        # don't use assert_python_ok() because it always enables faulthandler
         output = subprocess.check_output(args, env=env)
         self.assertEqual(output.rstrip(), b"False")