RegFreeWinRT support has bug in string handling that leads to failed DLL lookup

[BenJKuhn]

xlang/src/UndockedRegFreeWinRT/UndockedRegFreeWinRT/catalog.cpp

Line 202 in b950b15

RETURN_IF_FAILED(xmlReader->GetValue(&fileName, nullptr));

On this line, the fileName is held as a pointer to the XML parser buffer, which gets recycled frequently. The value is then used in an inner loop when reading class name, which moves the parser forward, potentially invalidating the data pointed to.

This causes the DLL name to be a bogus (but still typically valid) string, which doesn't lead to crashes, but does cause loadlibrary to fail. In some cases, this failure is masked by fallback logic in some projections that works, but is slower. In other cases, it leads to application failures.