cmd/compile/internal/types2: review of issues_test.go
The changes between (equivalent, and reviewed) go/types/issues_test.go
and issues_test.go can be seen by comparing patchset 1 and 3. The actual
change is just removing the "// UNREVIEWED" marker and making making
some minor code adjustments to match go/types's version more closely.
Change-Id: I26f3f700d12db69fc68161a6b0dc081a0e9cd0d4
Reviewed-on: https://go-review.googlesource.com/c/go/+/294473
Trust: Robert Griesemer <gri@golang.org> Reviewed-by: Robert Findley <rfindley@google.com>