[llvm] [MachineLICM] Use `RegisterClassInfo::getRegPressureSetLimit` (PR #211715)

[Nico Weber via llvm-commits]

nico wrote:

Looks like a bunch of tests are failing after this and have been for a few hours. What's the plan? Is a fix about to land, or should we revert?

https://github.com/llvm/llvm-project/pull/211715