Merge pull request #855 from masamitsu-murase/support_parser_dump_for_regexp_literal

parser_dump supports NODE_REGEX.

src/parse.y

@@ -5500,7 +5500,7 @@ parser_dump(mrb_state *mrb, node *tree, int offset)
     break;
 
   case NODE_REGX:
-    printf("NODE_REGX /%s/\n", (char*)tree->car->cdr->car);
+    printf("NODE_REGX /%s/%s\n", (char*)tree->car, (char*)tree->cdr);
     break;
 
   case NODE_SYM: