[llvm-branch-commits] [mlir] [mlir][test] Reorganize the test dialect (PR #89424)

[Mehdi Amini via llvm-branch-commits]

joker-eph wrote:

LG, but please make sure to remove all spurious headers from the commit description (seems like it should start at "This PR massively ...")

https://github.com/llvm/llvm-project/pull/89424