[Performance tests] Interactive/SelectAll.html throws an exception

[Performance tests] Interactive/SelectAll.html throws an exception
https://bugs.webkit.org/show_bug.cgi?id=124495

Reviewed by Antti Koivisto

Return a boolean indicating whether more values are needed or not in
PerfTestRunner.measureValueAsync so that runTest can terminate gracefully.

* Interactive/SelectAll.html:
(runTest): Don't schedule a timer for runTest if we've got enough values.
* resources/runner.js:
(PerfTestRunner.measureValueAsync): Returns true iff more values are needed.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@159421 268f45cc-cd09-0410-ab3c-d52691b4dbfc