cmd/go: git shallow fetches broken at CL 556358 [1.22 backport]

[gopherbot]

@bcmills requested issue #66147 to be considered for backport to the next 1.22 minor release.

@gopherbot, please backport to Go 1.22. This was an accidental regression in https://go.dev/cl/556358, and may cause increased client and server load when fetching modules directly from git repositories.

[gopherbot]

Change https://go.dev/cl/570737 mentions this issue: cmd/go/internal/modfetch: pass "-c" arguments to git before subcommands

[bcmills]

(CC @matloob @samthanawalla)

[gopherbot]

Closed by merging 0c53f93 to release-branch.go1.22.