internal/lsp: disable unimported completions for snippet tests
internal/lsp: disable unimported completions for snippet tests

Turns out that these were already disabled in the
golang.org/x/tools/internal/lsp tests, which is why we only ever save
the failures in golang.org/x/tools/internal/lsp/source tests. Discussing
the reasons that this is necessary on the issue, but I think completion
scoring in general needs to be centralized and documented, so hopefully
we can handle this case as part of that larger fix.

Fixes golang/go#38269

Change-Id: Ie1b615315e417ab8211a3580cf8f27cbdc3b74e4
Reviewed-on: https://go-review.googlesource.com/c/tools/+/227417
Run-TryBot: Rebecca Stambler <d7cf11e5f299d88ea8348366a9fc4f7c335c3afa@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Robert Findley <9179eee875d1ee628c37fb47d7e749e855ffd21f@google.com>

golang/tools,golang/tools,golang/tools,golang/tools,golang/tools