[clang] [CIR] Add cir-opt tool to exercise CIR dialect parsing (PR #128254)

[Andy Kaylor via cfe-commits]

================
@@ -0,0 +1,46 @@
+//===- cir-opt.cpp - CIR optimization and analysis driver -----*- C++ -*-===//
----------------
andykaylor wrote:

Thanks, I wasn't aware of that. I'll update this. I see that I also missed the file header on one of the other files I'm adding.

https://github.com/llvm/llvm-project/pull/128254