Reenable linux unwinder on Cross OS DAC build

[sdmaclea]

#31777 Disabled the unwinding of native frames in the Windows cross OS DAC build.

The root cause of the compilation errors will need to be addressed and this code will need to be reenabled

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[sdmaclea]

This is a bit harder than I initially had expected. As I understand it to use this code on Windows will also require a Windows port of libunwind.

@jkotas Mentioned
We have a libunwind implementation checked into the tree at https://github.com/dotnet/runtime/tree/master/src/coreclr/src/pal/src/libunwind

[sdmaclea]

Fixed by #37521

[tommcdon]

@sdmaclea can this issue be closed?