Remove the failure expectation of fast/forms/month/month-appearance-l10n.html

Bug: chromium:1020034
Change-Id: I01ba52316734556787f0aa0d76d5225040924056
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1894668Reviewed-by: Kent Tamura <tkent@chromium.org>
Commit-Queue: Frank Tang <ftang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#712329}

third_party/blink/web_tests/TestExpectations

@@ -5747,7 +5747,6 @@ crbug.com/940927 external/wpt/trusted-types/trusted-types-eval-reporting-no-unsa
 crbug.com/940927 external/wpt/trusted-types/eval-with-permissive-csp.tentative.html [ Failure ]
 
 # Sheriff 2019-10-31
-crbug.com/1020034 [ Mac10.10 ] fast/forms/month/month-appearance-l10n.html [ Failure ]
 crbug.com/1020036 [ Debug ] external/wpt/lifecycle/freeze.html [ Failure Pass ]
 
 # Temporarily disabled for landing datagrid Changes in devtools