gopls/internal/regtest: skip regtests for openbsd-amd64-64 on TryBots

This build is suddenly timing out with high frequency. This requires
investigation, but for now we must get builds passing again.

For golang/go#42789

Change-Id: I51dc5eab227cfb77cd3021438f1b161b21f69caf
Reviewed-on: https://go-review.googlesource.com/c/tools/+/272687
Run-TryBot: Robert Findley <rfindley@google.com>
Trust: Robert Findley <rfindley@google.com>
Reviewed-by: Rebecca Stambler <rstambler@golang.org>
gopls-CI: kokoro <noreply+kokoro@google.com>
TryBot-Result: Go Bot <gobot@golang.org>

gopls/internal/regtest/runner.go

@@ -232,6 +232,10 @@ type TestFunc func(t *testing.T, env *Env)
 func (r *Runner) Run(t *testing.T, files string, test TestFunc, opts ...RunOption) {
 	t.Helper()
 
+	if os.Getenv("GO_BUILDER_NAME") == "openbsd-amd64-64" && testing.Short() {
+		t.Skip("Skipping openbsd-amd64-64 due to golang.org/issues/42789.")
+	}
+
 	tests := []struct {
 		name      string
 		mode      Mode