cmd/go: add fips140 module selection mechanism [1.24 backport]

[gopherbot]

@FiloSottile requested issue #70200 to be considered for backport to the next 1.24 minor release.

The only thing left to do will be [...] populating inprocess.txt once the lab signs off on it. Hopefully these will both happen before Go 1.24.0, but updating inprocess.txt may also slip to a minor version.

CL 674916 creates the inprocess.txt file. @gopherbot, please open a Go 1.24 backport issue.

[gopherbot]

Change https://go.dev/cl/674935 mentions this issue: [release-branch.go1.24] lib/fips140: set inprocess.txt to v1.0.0

[mknyszek]

FYI, today is the last chance to land changes for the next minor release. The backport still needs review -- once reviewed I can submit. @FiloSottile @rolandshoemaker

[gopherbot]

Closed by merging CL 674935 (commit 04a9473) to release-branch.go1.24.