[llvm] Make a tablegen test match-table.td more robust. (PR #106508)

[Pierre van Houtryve via llvm-commits]

Pierre-vh wrote:

There is no pre-existing script unfortunately, I'm not sure what the best approach would be to get this done.
Writing an ad-hoc script doesn't sound too hard but it'll still take a bit of time to get right.

I understand if it's out of scope here. I guess we can land this and open an issue directly to come up with a more sustainable approach.

One easy approach would be to just read the file for the relevant function signatures, then read lines until we find the matching } and put all of that in a CHECK line. I don't think we'd need to base it off of an existing script like update_llc_test_checks

https://github.com/llvm/llvm-project/pull/106508