Web Inspector: performance: restore 'log 300 messages into console' test.

Web Inspector: performance: restore 'log 300 messages into console' test.
https://bugs.webkit.org/show_bug.cgi?id=76170

It was removed in order of transition from layout tests to perf tests.

Reviewed by Yury Semikhatsky.

PerformanceTests:

* inspector/console-300-lines.html: Added.

Source/WebCore:

* inspector/front-end/ConsoleView.js:
(WebInspector.ConsoleView.prototype._scheduleScrollIntoView.scrollIntoView):
(WebInspector.ConsoleView.prototype._scheduleScrollIntoView):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@104822 268f45cc-cd09-0410-ab3c-d52691b4dbfc