[clang] [clang][ExprConst] allow single element access of vector object to be constant expression (PR #101126)

[Vikram Hegde via cfe-commits]

vikramRH wrote:

### Merge activity

* **Aug 7, 6:38 AM EDT**: @vikramRH started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/101126).


https://github.com/llvm/llvm-project/pull/101126