Bug 1406897: use quit() instead of top-level return in test to fix bustage on a CLOSED TREE; r=me

js/src/jit-test/tests/wasm/regress/onlyjsiter-while-wasm.js

@@ -1,5 +1,5 @@
 if (typeof evalInCooperativeThread === 'undefined')
-    return;
+    quit();
 
 try {
     evalInCooperativeThread(`