cmd/go: go list fails with submodules which have test-only dependencies [1.19 backport]

[gopherbot]

@bcmills requested issue #60667 to be considered for backport to the next 1.19 minor release.

@gopherbot, please backport to Go 1.19 and 1.20. This is a regression introduced in a previous patch release.

[gopherbot]

Change https://go.dev/cl/502017 mentions this issue: [release-branch.go1.19] cmd/go: omit checksums for go.mod files needed for go version lines more often in pre-1.21 modules

[bcmills]

Approving as a fix for a regression in the previous minor release.

[gopherbot]

Closed by merging 1d85bce to release-branch.go1.19.