cmd/compile: Go 1.22 build fails with 1.21 PGO profile on internal/saferio change [1.22 backport]

[gopherbot]

@prattmic requested issue #65615 to be considered for backport to the next 1.22 minor release.

@gopherbot Please backport to 1.21 and 1.22. This is a build failure with PGO if a hot function is changed from non-generic to generic. Only workarounds are to rename the symbol or disable PGO.

[gopherbot]

Change https://go.dev/cl/563016 mentions this issue: [release-branch.go1.22] cmd/compile: fail noder.LookupFunc gracefully if function generic

[gopherbot]

Closed by merging 6cbe522 to release-branch.go1.22.