Mark testrunner-crashreporter test insignificant on Mac.
Mark testrunner-crashreporter test insignificant on Mac.

CrashReporter sometimes decides that there have been
"Too many crashes in rapid succession" and stops generating crash logs.
I can't figure out what triggers this behavior, so the only choices are
either to mock CrashReporter for the test, or mark the test as
insignificant until the problem can be addressed.

Task-number: QTQAINFRA-488
Change-Id: Ibe9ec1c01f88786a83091cad62853f79bd71b1ed
Reviewed-by: Toby Tomkins <23ead35e36f9890dd80f47acf9947179b1bd7fe7@nokia.com>

tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa,tsarajar/qtqa