[llvm] [Intrinsics] Make `patchpoint.i64` generic on its return type (PR #85911)

[Matt Arsenault via llvm-commits]

https://github.com/arsenm commented:

lgtm, but I know nothing about these intrinsics (but arbitrary type constraints on intrinsics are often bad)

https://github.com/llvm/llvm-project/pull/85911