Because a semi-arbitrary subset of tests are run in a too-many-failures build, we can't
really use them to perform regression analysis. The only time we want to pay attention to
too-many-failures builds is when we're trying to explain when the current bout of
too-many-failures started.

Fixes <http://webkit.org/b/64106> TestFailures page sometimes claims a test started failing
in a build that didn't even run it (because it exited early due to too many failues)

Patch by Adam Roben <aroben@apple.com> on 2011-07-07
Reviewed by David Kilzer.

* BuildSlaveSupport/build.webkit.org-config/public_html/TestFailures/LayoutTestHistoryAnalyzer.js:
(LayoutTestHistoryAnalyzer.prototype._incorporateBuildHistory): Removed old, broken
too-many-failures handling that would cause us to blame builds that didn't even run a given
test for breaking it. Instead, skip over all too-many-failures builds unless the most recent
build was itself a too-many-failures build.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@90571 268f45cc-cd09-0410-ab3c-d52691b4dbfc