go.mod: Add indirect exclusions/redirections from golang-protobuf upgrade

The golang-protobuf upgrade brought in new dependencies, which broke the
hermeticity of our go.mod redirections. Fix those up so they get
excluded or redirected to the locations in the tree.

Test: cd build/soong/cc; go test .
Change-Id: I012d11fad3b5509b213093e3c5889a27e641b868