LLVM: lower optional types as byref=true

This is a possible workaround for
https://github.com/llvm/llvm-project/issues/56585

On my computer it makes stage3-release go from false positive
compilation errors on the behavior tests to "segmentation fault".
Is this forwards progress or backwards progress? I have no idea.

See #11450
65bc4d915dAndrew Kelley committed on 7/19/2022, 6:22:48 PMparentc26d9f6
1 file changedLine totals unavailable