[llvm] OrcV2: also set COFF flag overrides when custom linking layer is used (PR #129533)

[Wenzel Jakob via llvm-commits]

wjakob wrote:

The other option honestly sounds fine as well :). The main requirement is that there is a way to pack code+data into a single section, via the C API.

https://github.com/llvm/llvm-project/pull/129533