Shenandoah: heap may be corrupted following OutOfMemoryError during Class Initialization

The jtreg test: runtime/ClassInitErrors/TestOutOfMemoryDuringInit.java sometimes crashes with an assertion error (is_oop(obj) failed) or a SIGSEGV error. This issue was first detected on a development branch of Generational Shenandoah, but it has now been reproduced on tip with single-generation Shenandoah.