[dev.typeparams] cmd/compile/internal/types: review of errors_test.go
[dev.typeparams] cmd/compile/internal/types: review of errors_test.go

The changes between (equivalent, and reviewed) go/types/errors_test.go
and errors_test.go can be seen by comparing patchset 1 and 2. The actual
change is just removing the "// UNREVIEWED" marker.

Change-Id: I74de039b9e655445f0407a0203ac52a95c6c8a40
Reviewed-on: https://go-review.googlesource.com/c/go/+/291179
Trust: Robert Griesemer <a6752097faebf1f02d80107d77a9be009089afe3@golang.org>
Reviewed-by: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>

CAFxX/go,golang/go,cloudflare/go,cloudflare/go,cloudflare/go,nawawi/go,CAFxX/go,golang/go,CAFxX/go,golang/go,nawawi/go,golang/go,nawawi/go,cloudflare/go,nawawi/go,nawawi/go,cloudflare/go,CAFxX/go,CAFxX/go,cloudflare/go,golang/go,golang/go,cloudflare/go,CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,nawawi/go,golang/go,CAFxX/go,golang/go,cloudflare/go