cmd/compile: Go 1.22 changes support for modules that declare `go 1.0` [1.22 backport]

[gopherbot]

@bcmills requested issue #65528 to be considered for backport to the next 1.22 minor release.

@gopherbot, please backport to Go 1.22. This was a regression in 1.22.0 and the fix is trivial.

[gopherbot]

Change https://go.dev/cl/562815 mentions this issue: cmd/compile: accept -lang=go1 as -lang=go1.0

[gopherbot]

Closed by merging fb86598 to release-branch.go1.22.