[clang] [llvm] [llvm:ir] Add support for constant data exceeding 4GiB (PR #126481)

[Eli Friedman via cfe-commits]

https://github.com/efriedma-quic approved this pull request.

LGTM.

(I'll merge once the premerge checks come back.)

https://github.com/llvm/llvm-project/pull/126481