Fix regression in empty `.go` file filtering for nogo (#3832)

* Fix regression in empty `.go` file filtering for nogo

6236dd80670cdfe1477a484e98e3f82dbcc28fe9 regressed the nogo exclusion
logic for the empty `.go` file generated for targets that otherwise
don't contain any `.go` files. The test had been silently disabled a
while ago when the name pattern for the empty file was changed.

This is fixed by reintroducing the exclusion logic and making the test
more strict.

* Update go/tools/builders/compilepkg.go

Co-authored-by: Tyler French <66684063+tyler-french@users.noreply.github.com>

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Co-authored-by: Tyler French <66684063+tyler-french@users.noreply.github.com>
2 files changed