cmd/go: in Go 1.17+ modules, add indirect go.mod dependencies separately from direct ones

Fixes #45965

Change-Id: If5c0d7b29e9f81be0763f3fa68051d4ef5419990
Reviewed-on: https://go-review.googlesource.com/c/go/+/325922


Trust: Bryan C. Mills <bcmills@google.com>
Reviewed-by: Michael Matloob <matloob@golang.org>