Rework RegExp engine and add support for proper unicode matching (#3746)

This change includes several bugfixes, general improvements, and support
for additional features.
- Added full support for web compatibility syntax defined in Annex B
- Implemented parsing and matching patterns in unicode mode
- Fixed capture results when iterating with nested capturing groups
- Significantly reduced regexp bytecode size
- Reduced stack usage during regexp execution
- Improved matching performance

JerryScript-DCO-1.0-Signed-off-by: Dániel Bátyai dbatyai@inf.u-szeged.hu

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

@@ -2723,6 +2723,14 @@ parser_parse_script (const uint8_t *arg_list_p, /**< function argument list */
       jcontext_raise_exception (ECMA_VALUE_NULL);
       return ECMA_VALUE_ERROR;
     }
+
+    if (parser_error.error == PARSER_ERR_INVALID_REGEXP)
+    {
+      /* The RegExp compiler has already raised an exception. */
+      JERRY_ASSERT (jcontext_has_pending_exception ());
+      return ECMA_VALUE_ERROR;
+    }
+
 #if ENABLED (JERRY_ERROR_MESSAGES)
     const lit_utf8_byte_t *err_bytes_p = (const lit_utf8_byte_t *) parser_error_to_string (parser_error.error);
     lit_utf8_size_t err_bytes_size = lit_zt_utf8_string_size (err_bytes_p);