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

[David Blaikie via cfe-commits]

dwblaikie wrote:

> I.e., two `DIGlobalVariableExpression`s for the same `DIGlobalVariable`, which AFAICT would confuse `DwarfDebug` at the moment, which expects there to be a 1-to-1 mapping.

Would confuse `DwarfDebug` without your changes/this patch? Or only with this patch?
(& hopefully there's some way to reach the merge globals functionality/problem/interesting IR from clang itself - but I guess even if it isn't, this is still a demonstration of representational issues)

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