[clang] [clang] Implement constexpr heap allocation alignments (PR #174549)

[Nikolas Klauser via cfe-commits]

philnik777 wrote:

> Yes that's fine, I just can't have a single patch of the PR to test because the first commit doesn't rebase cleanly.

This isn't my branch, so I'm not sure I can easily rebase (at least it caused problems before when I tried). Is there a reason you can't merge instead of rebasing?

https://github.com/llvm/llvm-project/pull/174549