[clang] [clang][DebugInfo] Attach DW_AT_const_value to static data-member definitions if available (PR #72730)

[J. Ryan Stinnett via cfe-commits]

https://github.com/jryans approved this pull request.

> This patch makes sure we encode the constant in a `DIExpression` on definitions, which is tested. And we have tests for ensuring that `DW_OP_constu` expressions get turned into `DW_AT_const_value`s (I know of at least `llvm/test/DebugInfo/Generic/dwarf5-debug-info-static-member.ll`)

Ah okay, then with that in mind, I think the test changes here are likely enough to merge. 🙂 

https://github.com/llvm/llvm-project/pull/72730