Add RegExp recursion depth limit (#2543)

The regexp engine does not have any recursion depth check, thus it can cause problems with various regexps. Added a new build option `--regexp-recursion-limit N` whose
default value is 0, which is for unlimited recursion depth. Also added a build-option-test.

Fixes #2448
Fixes #2190

JerryScript-DCO-1.0-Signed-off-by: Istvan Miklos imiklos2@inf.u-szeged.hu

jerry-core/parser/regexp/re-compiler.h

@@ -41,6 +41,9 @@ typedef struct
   uint32_t num_of_captures;          /**< number of capture groups */
   uint32_t num_of_non_captures;      /**< number of non-capture groups */
   uint32_t highest_backref;          /**< highest backreference */
+#ifdef REGEXP_RECURSION_LIMIT
+  uint32_t recursion_counter;        /**< RegExp recursion counter */
+#endif /* REGEXP_RECURSION_LIMIT */
   re_bytecode_ctx_t *bytecode_ctx_p; /**< pointer of RegExp bytecode context */
   re_token_t current_token;          /**< current token */
   re_parser_ctx_t *parser_ctx_p;     /**< pointer of RegExp parser context */