cmd/go: prefer to report mismatched module paths over mismatched major versions

What version of Go are you using (go version)?

Does this issue reproduce with the latest release?

Yes

What operating system and processor architecture are you using (go env)?

What did you do?

Tried to run go mod tidy in github.com/twitchscience/kinsumer

What did you expect to see?

I expected it to report correctly that the project github.com/myesui/uuid is the one that uses gopkg.in/stretchr/testify.v1. However, it's reporting that twinj/uuid incorrectly is the one that is using.

What did you see instead?

go: finding gopkg.in/stretchr/testify.v1 v1.4.0
github.com/twitchscience/kinsumer imports
	github.com/twinj/uuid tested by
	github.com/twinj/uuid.test imports
	gopkg.in/stretchr/testify.v1/assert: cannot find module providing package gopkg.in/stretchr/testify.v1/assert

How the module looks like:

module github.com/twitchscience/kinsumer

go 1.13

require (
	github.com/aws/aws-sdk-go v1.24.2
	github.com/cactus/go-statsd-client/statsd v0.0.0-20190906215803-47b6058c80f5
	github.com/myesui/uuid v1.0.0 // indirect
	github.com/stretchr/testify v1.4.0
	github.com/twinj/uuid v1.0.0

	golang.org/x/net v0.0.0-20190918130420-a8b05e9114ab // indirect
	golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e
)

The strangest thing is that I see no mention of myesui/uuid in the vendored directory.