cmd/dist: skip non-std tests on js/wasm

After the std tests, most of the rest of the tests aren't applicable
to js/wasm. (anything with -cpu=>1, cgo, etc)

Skip them all for now. We can incrementally re-enable them over time
as the js/wasm port is fleshed out. But let's get the builder column
black again so we can enable trybots and keep it black.

Updates #26014
Updates #26015
Updates #18892

Change-Id: I8992ed3888f598fa42273ce8646a32d62ce45b1d
Reviewed-on: https://go-review.googlesource.com/120575
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Andrew Bonventre <andybons@golang.org>

src/cmd/dist/test.go

@@ -446,7 +446,7 @@ func (t *tester) registerTests() {
 		})
 	}
 
-	if t.race {
+	if t.race || goos == "js" {
 		return
 	}