ci: add paralleltestctx to lint/go (#19369)

Closes https://github.com/coder/internal/issues/884

We're adding this as a `go run` in `lint/go` for now, since adding it to
golangci-lint ourselves involves recompiling golangci-lint and then
running that new binary. I'll look into proposing it being added to the
public golangci-lint linters.

Doesn't appear to cause the lint ci job to take any longer, which is
nice.

enterprise/coderd/schedule/template_test.go

@@ -222,6 +222,7 @@ func TestTemplateUpdateBuildDeadlines(t *testing.T) {
 	for _, c := range cases {
 		t.Run(c.name, func(t *testing.T) {
 			t.Parallel()
+			ctx := testutil.Context(t, testutil.WaitShort)
 
 			user := quietUser
 			if c.noQuietHours {