[llvm] [mlir] [mlir][core] Add an MLIR "pattern catalog" generator (PR #146228)

[Jeremy Kun via llvm-commits]

j2kun wrote:

After discussing with @matthias-springer it seems the dialect conversion framework is not immediately compatible with this change (in large part because the conversion rewriter is itself implemented as a listener that overrides much of the default behavior to do stateful things). The immediate result is that the catalog only includes "insert op" actions for dialect conversion patterns.

I am looking into a different way to support this for dialect conversion, until (perhaps in the distant future) dialect conversion is refactored so that it can operate with listeners more smoothly.

If it's OK, I will split that into a different PR, and so the last thing I need here is a lit test that ensures the debug output is produced in a pass that uses the greedy driver.

https://github.com/llvm/llvm-project/pull/146228