Python2 compatibility: fix flake8 report F632 F821

use '!=' instead of 'is not' with str
FileNotFoundError isn't exist in python2.7, use IOError instead.


Bug: chromium:948812
Change-Id: I241ff8a9321d612f2371a2a2e2deae948fa180e5
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1549168
Commit-Queue: Sergiy Belozorov <sergiyb@chromium.org>
Reviewed-by: Sergiy Belozorov <sergiyb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60661}

tools/locs.py

@@ -21,6 +21,12 @@ import tempfile
 import time
 from pathlib import Path
 
+# for py2/py3 compatibility
+try:
+    FileNotFoundError
+except NameError:
+    FileNotFoundError = IOError
+
 ARGPARSE = argparse.ArgumentParser(
     description=("A script that computes LoC for a build dir or from a"
                  "compile_commands.json file"),

tools/testrunner/outproc/mkgrokdump.py

@@ -20,7 +20,7 @@ class OutProc(base.OutProc):
     diff = difflib.unified_diff(expected_lines, actual_lines, lineterm="",
                                 fromfile="expected_path")
     diffstring = '\n'.join(diff)
-    if diffstring is not "":
+    if diffstring != "":
       if "generated from a non-shipping build" in output.stdout:
         return False
       if not "generated from a shipping build" in output.stdout: