Fix key iteration in ecma_op_map_foreach (#2855)

This patch fixes #2852 and fixes #2853 as well.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu

tests/jerry/es2015/regression-test-issue-2852.js

@@ -0,0 +1,29 @@
+// 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 createMap (count) {
+  var map = new Map()
+  for (var i = 0; i < count; i++) {
+    map.set(i)
+  }
+  return map
+}
+
+var counter = 0;
+createMap(2000).forEach(function ($, key) {
+  counter++;
+  $ += key
+})
+
+assert(counter === 2000);

tests/jerry/es2015/regression-test-issue-2853.js

@@ -0,0 +1,27 @@
+// 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 map = new Map()
+map.set()
+map.set('bar')
+
+var count = 0
+map.forEach(function () {
+  if (count === 0) {
+    map.delete('bar')
+  }
+  count++;
+})
+
+assert(count === 1);