Bug 1261649 - Do not use bare ** in a new test; r=sfink

--HG--
extra : rebase_source : 488d04e29c674e355cfa4a1a4776f12d8410b7bf

js/src/jit-test/tests/gc/bug-1259490.js

@@ -1,4 +1,9 @@
+try { eval("3 ** 4") } catch (e if e instanceof SyntaxError) { quit(); };
+eval(`
+
 gczeal(8);
 for (var k = 0; k < 99; ++k) {
     uneval(-(0 ** (Object | 0 * Object)))
 }
+
+`)