[clang] [CIR] Refactor floating point type constraints (PR #138112)

[Henrich Lauko via cfe-commits]

xlauko wrote:

### Merge activity

* **May 2, 3:21 AM EDT**: @xlauko merged this pull request with [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/138112).


https://github.com/llvm/llvm-project/pull/138112