Merge PerfTestRunner._run_single_test into PerfTestRunner._run_tests_set
https://bugs.webkit.org/show_bug.cgi?id=111142

Reviewed by Adam Barth.

Merged _run_single_test into _run_tests_set. The code looks much cleaner now.

Also removed _print_status since it's never used anywhere.

* Scripts/webkitpy/performance_tests/perftestsrunner.py:
(PerfTestsRunner.run):
(PerfTestsRunner._run_tests_set):
* Scripts/webkitpy/performance_tests/perftestsrunner_integrationtest.py:
(MainTest.run_test):
(MainTest.test_run_test_set):
(MainTest.test_run_test_set_kills_drt_per_run):
(MainTest.test_run_test_set_for_parser_tests):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@144421 268f45cc-cd09-0410-ab3c-d52691b4dbfc