Cleanup invalidation reason strings

This patch cleans up the reason strings to not have periods. Additionally,
a typo has been fixed in InspectorTraceEvents.

BUG=410701,424451

Review URL: https://codereview.chromium.org/650993004

git-svn-id: svn://svn.chromium.org/blink/trunk@184330 bbb929c8-8fbe-4397-9dbb-9b2b20218538