cmd/compile: package-level variable initialization with constant dependencies doesn't match order specified in Go spec [1.22 backport]

[gopherbot]

@griesemer requested issue #66575 to be considered for backport to the next 1.22 minor release.

@gopherbot please consider this for backport to 1.22, it's a bug with respect to the spec.

[gopherbot]

Change https://go.dev/cl/590395 mentions this issue: [release-branch.go1.22] cmd/compile: put constants before variables in initialization order

[gopherbot]

Closed by merging 5159a71 to release-branch.go1.22.