Make Array.prototype.unshift method conform to ES11 (#4128)

Changes:
- Since ES6 Array.prototype.unshift shouldn't iterate
over the array elements if argument count is 0.
- Add proper guard for a check introduced in ES6.
- Update comments to reference to ES5.1 and ES11 specs too.

JerryScript-DCO-1.0-Signed-off-by: Csaba Osztrogonác csaba.osztrogonac@h-lab.eu

tests/jerry/es.next/array-prototype-unshift.js

@@ -0,0 +1,17 @@
+// 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.
+
+var arrayLike = {get 5() { throw "shouldn't throw"; }};
+arrayLike.length = 10;
+Array.prototype.unshift.call(arrayLike);

tests/jerry/es5.1/array-prototype-unshift.js

@@ -0,0 +1,22 @@
+// 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.
+
+var arrayLike = {get 5() { throw "should throw"; }};
+arrayLike.length = 10;
+try {
+  Array.prototype.unshift.call(arrayLike);
+  assert(false);
+} catch (error) {
+  assert(error == "should throw");
+}

tests/test262-esnext-excludelist.xml

@@ -170,7 +170,6 @@
   <test id="built-ins/Array/prototype/splice/create-species.js"><reason></reason></test>
   <test id="built-ins/Array/prototype/splice/property-traps-order-with-species.js"><reason></reason></test>
   <test id="built-ins/Array/prototype/splice/throws-if-integer-limit-exceeded.js"><reason></reason></test>
-  <test id="built-ins/Array/prototype/unshift/clamps-to-integer-limit.js"><reason></reason></test>
   <test id="built-ins/ArrayBuffer/data-allocation-after-object-creation.js"><reason></reason></test>
   <test id="built-ins/ArrayBuffer/proto-from-ctor-realm.js"><reason></reason></test>
   <test id="built-ins/ArrayBuffer/prototype-from-newtarget.js"><reason></reason></test>