Up the cap on test failures tolerated by the EWS so the mac-ews can run to completion

Up the cap on test failures tolerated by the EWS so the mac-ews can run to completion
https://bugs.webkit.org/show_bug.cgi?id=76567

Reviewed by Eric Seidel.

Current the AppleMac port has slightly more failures than we allow on
the EWS, causing the mac-ews to spin.  This patch ups the limit a bit,
which should hopefully let the mac-ews run to completion.  Once
AppleMac has fewer failures, we can lower the cap again.

* Scripts/webkitpy/tool/bot/layouttestresultsreader_unittest.py:
(LayoutTestResultsReaderTest.test_layout_test_results):
* Scripts/webkitpy/tool/steps/runtests.py:
(RunTests):
* Scripts/webkitpy/tool/steps/steps_unittest.py:

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@105319 268f45cc-cd09-0410-ab3c-d52691b4dbfc