Bug testcase for Array .push() fastpath bug

tests/ecmascript/test-bug-array-fastpath-push-retval.js

@@ -0,0 +1,19 @@
+/*
+ *  https://github.com/svaarala/duktape/pull/1154
+ */
+
+/*===
+number 5
+===*/
+
+function test() {
+    var arr = [ 1, 2, 3 ];
+    var ret = arr.push('foo', 'bar');
+    print(typeof ret, ret);
+}
+
+try {
+    test();
+} catch (e) {
+    print(e.stack || e);
+}