[llvm] [llvm-ir2vec][MIR2Vec] Supporting MIR mode in triplet and entity generation (PR #164329)

[S. VenkataKeerthy via llvm-commits]

svkeerthy wrote:

### Merge activity

* **Oct 23, 5:50 PM UTC**: A user started a stack merge that includes this pull request via [Graphite](https://app.graphite.dev/github/pr/llvm/llvm-project/164329).


https://github.com/llvm/llvm-project/pull/164329