Moves GWTTestCase to Impl#setUncaughtExceptionHandlerForTest.

This will prevent the competition between the test and production uncaught exception handlers.
This change also introduces GWTTestCase#reportUncaughtException to enable test cases to change the behavior in order to test uncaught exceptions.

Fixes issue 5016

Change-Id: I8d32c6f4ff4cbcd55f238116b8bcc4c8685d6f35
Review-Link: https://gwt-review.googlesource.com/#/c/2190/


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@11569 8db76d5a-ed1c-0410-87a9-c151d255dfc7
9 files changed