Revert "try more test offscreen"

This reverts commit 4cfe1b44.

QDEBUG : KateFoldingTest::testCrash311866() !!! Does the next line crash?
pure virtual method called
terminate called without an active exception
Received signal 6 (SIGABRT)
         testCrash311866 function time: 275ms, total time: 275ms
=== Stack trace ===
ptrace: Operation not permitted.
=== End of stack trace ===
      Start 65: bug286887