Fix crash in DAC enum memory code that brings down createdump #104939
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Either a recent change in a MT's virtual method slot allocation or createdump is just getting unlucky now and the slot hasn't been filled in yet is causing this crash. The DAC EnumMemoryRegions API is calling ExceptionTypeOverridesStackTraceGetter() which enumerates all the virtual method slots in the ExceptionObject's MT looking for "get_StackTrace" and check if it has been overridden. All the code involved hasn't change in a very long time.
GetMethodDescForSlot gets called for a slot that has no PCODE (GetRestoredSlot() returns null). There is a comment in that function about slots not being filled in yet and code on the runtime side (ifdef'ed out in the DAC) that fills it in.
The stack trace of the crash: