Fix WebCore.Scripts.ParserBlocking.TimeBetweenLoadedAndCompiled

1) The results were skewed by scripts from the same resource being ran several
times (so we saw times > 10 s).

2) Script run time was included in the measurement, and it shouldn't be.

WebCore.Scripts.Deferred.TimeBetweenLoadedAndCompiled is removed for now (to be
fixed later, when it's really needed). Tracking whether a deferred script was
already loaded when requested is more complicated.

BUG=

Review URL: https://codereview.chromium.org/551333002

git-svn-id: svn://svn.chromium.org/blink/trunk@181641 bbb929c8-8fbe-4397-9dbb-9b2b20218538