Declaration in the head of a for-of loop can't have an initializer (#4804)

JerryScript-DCO-1.0-Signed-off-by: Robert Sipka robert.sipka@h-lab.eu

Co-authored-by: Robert Sipka <robert.sipka@h-lab.eu>

tests/jerry/initializer-in-for-of-statement-head.js

@@ -0,0 +1,25 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+function parse(txt) {
+    try {
+        eval(txt)
+        assert(false)
+    } catch (e) {
+        assert(e instanceof SyntaxError)
+    }
+}
+
+parse("for (var x = 1 of []) { }")