[JITLink][AArch32] Fix MSVC error on missing constexpr capture

The Windows MSVC builder complains: 'ImmMask' cannot be implicitly captured because no default capture mode has been
specified
When adding the explicit capture, Clang warns: Lambda capture 'ImmMask' is not required to be captured for this use

This seems to be a known implementation divergence. Using a default value capture should avoid the issue.