cmd/go: extend the ignore directive for indexed modules
For modules that have already been indexed, we can skip ignored paths.
We already skip 'testdata' and '_' for this case so we can extend the
ignore directive for this case as well.
Updates: #42965
Change-Id: I076a242ba65c7b905b9dc65dcfb0a0247cbd68d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/674076 Reviewed-by: Michael Matloob <matloob@google.com> Reviewed-by: Michael Matloob <matloob@golang.org>
Auto-Submit: Sam Thanawalla <samthanawalla@google.com>
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