[clang] [HIP] Do not apply 'externally_initialized' to constant device variables (PR #182157)

[Matt Arsenault via cfe-commits]

arsenm wrote:

> This is intended because device programs can be modified beyond the normal lifetime expected by the optimization pipeline

Can you be more specific? What case could be modified by something in the current IR?

https://github.com/llvm/llvm-project/pull/182157