[llvm] [mlir] [TOSA] Add Tosa_Shape type and ConstShapeOp (PR #122547)

[via llvm-commits]

Jerry-Ge wrote:

> Thanks for the PR @Jerry-Ge! I had a look and left a few comments below, largely they're just questions along with some requests for better test coverage

Thanks Luke! This patch is primarily for aligning the internal and upstream branches. To keep things clean, I will achieve this in multiple patches. 

https://github.com/llvm/llvm-project/pull/122547