Memory leaks in mscordacwks

[goldshtn]

There are multiple memory leaks ranging from tiny (12 bytes each time) to somewhat serious (several dozen KB) in mscordacwks's implementation of the IXCLR* interfaces. Specifically, it doesn't seem to be hardened against invalid input. There is one repro here and you could construct many more. Notably, DacError uses the EX_THROW macro, which seems to leak 12 bytes of memory because it allocates the exception object with new (?!).

[MattWhilden]

Thanks for reporting the issue. Adding someone from the diagnostics team to potentially comment. @noahfalk