Fix escape sequence parsing in lexer_compare_identifier_to_current. (#2409)

Furthermore do not allow escape sequences in object initializer
get/set functions.

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

tests/jerry/regression-test-issue-2409.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.
+
+// Must be a success.
+eval('g\\u0065t: break get')
+
+try {
+  // Must be a fail.
+  eval('({ g\\u0065t a() {} })')
+  assert(false);
+} catch (e) {
+  assert(e instanceof SyntaxError);
+}
+
+// Must be a success.
+eval('({ g\\u0065t: 5 })')