Make executeSlicesUntilClumpsFinished failure test have a reliable failure mode

[Devika-Tantry]

The test The Vireo EggShell executeSlicesUntilClumpsFinished API reports error when the Vireo runtime stops execution test is intended to verify that the user can correctly observe both graceful errors and critical errors in Vireo execution. As Vireo runs asynchronously this test is useful to make sure that both graceful errors and exceptions are reported correctly to asynchronous callers.

Currently the test triggers a critical failure by assuming that a large allocation will cause a segmentation fault. This behavior is not reliable as we may change large allocation failure modes in the future. An instruction should be added that can explicitly trigger a segmentation fault so the test can verify handling of critical Vireo failures.