[regexp] catch stack overflow when parsing back references.

src/regexp/regexp-parser.cc

Index: src/regexp/regexp-parser.cc
diff --git a/src/regexp/regexp-parser.cc b/src/regexp/regexp-parser.cc
index 0df12dcbab7e73357571665090183876092275c6..6db8d04defbd69449e60d970b8881528e2497909 100644
--- a/src/regexp/regexp-parser.cc
+++ b/src/regexp/regexp-parser.cc
@@ -387,7 +387,8 @@ RegExpTree* RegExpParser::ParseDisjunction() {
           case '8':
           case '9': {
             int index = 0;
-            if (ParseBackReferenceIndex(&index)) {
+            bool is_backref = ParseBackReferenceIndex(&index CHECK_FAILED);
+            if (is_backref) {
               if (state->IsInsideCaptureGroup(index)) {
                 // The back reference is inside the capture group it refers to.
                 // Nothing can possibly have been captured yet, so we use empty