[clang] [CIR] Infer MLIRContext in attr builders when possible (PR #136741)

[Henrich Lauko via cfe-commits]

xlauko wrote:

### Merge activity

* **Apr 23, 1:51 AM EDT**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/136741).


https://github.com/llvm/llvm-project/pull/136741