cmd/dist: reenable testing of Examples for js/wasm

Testing Examples for js/wasm is supported as of ac56baa0, so we can
reenable them.

This reverts CL 119377 (commit 9a917130).

Fixes #25933

Change-Id: I0f228a3ec385dbe9573d3c33e42dccd4488d7152
Reviewed-on: https://go-review.googlesource.com/c/go/+/167800Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

src/cmd/dist/test.go

@@ -326,8 +326,6 @@ func (t *tester) registerStdTest(pkg string) {
 			}
 			if t.compileOnly {
 				args = append(args, "-run=^$")
-			} else if goos == "js" && goarch == "wasm" {
-				args = append(args, "-run=^Test") // exclude examples; Issue 25913
 			}
 			args = append(args, stdMatches...)
 			cmd := exec.Command("go", args...)
@@ -1270,9 +1268,6 @@ func (t *tester) runFlag(rx string) string {
 	if t.compileOnly {
 		return "-run=^$"
 	}
-	if rx == "" && goos == "js" && goarch == "wasm" {
-		return "-run=^Test" // exclude examples; Issue 25913
-	}
 	return "-run=" + rx
 }