Consider module_utils deps when running tests. (#21382)

* Skip pep8 analysis when --explain is used.
* Fix return type annotations.
* Match line length requirement of PEP 8 config.
* Consider module_utils deps when running tests.

test/runner/lib/executor.py

@@ -165,7 +165,7 @@ def generate_egg_info(args):
 def generate_pip_install(command):
     """
     :type command: str
-    :return: list[str] | None
+    :rtype: list[str] | None
     """
     constraints = 'test/runner/requirements/constraints.txt'
     requirements = 'test/runner/requirements/%s.txt' % command
@@ -861,6 +861,9 @@ def command_sanity_pep8(args, targets):
     if stderr:
         raise SubprocessError(cmd=cmd, status=status, stderr=stderr)
 
+    if args.explain:
+        return
+
     pattern = '^(?P<path>[^:]*):(?P<line>[0-9]+):(?P<column>[0-9]+): (?P<code>[A-Z0-9]{4}) (?P<message>.*)$'
 
     results = [re.search(pattern, line).groupdict() for line in stdout.splitlines()]