[llvm] [GlobalISel] Add a update_givaluetracking_test_checks.py script (PR #140296)

[David Green via llvm-commits]

davemgreen wrote:

> Could this be integrated into `update_mir_test_checks.py` if we see `-passes="print<gisel-value-tracking>"` in the RUN line?

Yes - sorry. Just as there is a difference between update_test_checks.py and update_analysis_test_checks.py, there is quite a difference between what update_mir_test_checsks and this new script handle.

https://github.com/llvm/llvm-project/pull/140296