[GTK][WPE] Improve the way glib tests are run

[GTK][WPE] Improve the way glib tests are run
https://bugs.webkit.org/show_bug.cgi?id=181674

Patch by Carlos Garcia Campos <cgarcia@igalia.com> on 2018-01-16
Reviewed by Žan Doberšek.

Stop using gtester external program and use our own tester from python directly. This way we no longer need to
parse the tests output to get the results which is causing problems in WPE bot. We can now differentiate between
tests failing due to an expected assert in the test and unexpected crashes.
This also fixes a bug in previous code where we failed to properly detect tests timing out, because gtester was
not showing the subtest name in stdout in case of timeouts.
I've lowered the default timeout from 10 to 5, since we are now properly handling the timeout for every test
case. I've also removed the verbose option, since it was only used by gtester and we now always show the result
of every test case.

* glib/api_test_runner.py:
(TestRunner._run_test_glib): Use GLibTestRunner.
(TestRunner._run_google_test): Wrote tests timing out to stdout too.
(add_options):
* glib/glib_test_runner.py: Added.
(TestTimeout):
(Message):
(Message.__init__):
(Message.create):
(Message.create.read_unsigned):
(Message.create.read_double):
(Message.create.read_string):
(GLibTestRunner):
(GLibTestRunner.__init__):
(GLibTestRunner._process_data):
(GLibTestRunner._process_message):
(GLibTestRunner._read_from_pipe):
(GLibTestRunner._read_from_stderr):
(GLibTestRunner._start_timeout):
(GLibTestRunner._start_timeout._alarm_handler):
(GLibTestRunner._stop_timeout):
(GLibTestRunner._subtest_start):
(GLibTestRunner._subtest_message):
(GLibTestRunner._subtest_stderr):
(GLibTestRunner._subtest_end):
(GLibTestRunner.run):

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@226967 268f45cc-cd09-0410-ab3c-d52691b4dbfc