Fix object initializer prescanning issues. (#2563)

This patch fixes incorrect syntax errors reported by the prescanner for
ES5.1 getter/setter property initializers and ES2015 computed properties.

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

jerry-core/parser/js/js-lexer.c

@@ -2427,6 +2427,9 @@ lexer_scan_identifier (parser_context_t *context_p, /**< context */
     lexer_next_token (context_p);
 
     if (context_p->token.type == LEXER_LITERAL
+#ifndef CONFIG_DISABLE_ES2015_OBJECT_INITIALIZER
+        || context_p->token.type == LEXER_LEFT_SQUARE
+#endif /* !CONFIG_DISABLE_ES2015_OBJECT_INITIALIZER */
         || context_p->token.type == LEXER_RIGHT_BRACE)
     {
       return;