Don't break when a match is found, if we are looking for the longest match

regex/matching.go

@@ -287,7 +287,9 @@ func findAllSubmatchHelper(start *nfaState, str []rune, offset int, numGroups in
 			if currentState.isLast {
 				currentState.threadGroups[0].EndIdx = idx
 				match = append([]Group{}, currentState.threadGroups...)
-				break
+				if !preferLongest {
+					break
+				}
 			} else if !currentState.isAlternation && !currentState.isKleene && !currentState.isQuestion && !currentState.groupBegin && !currentState.groupEnd && currentState.assert == noneAssert { // Normal character
 				if currentState.contentContains(str, idx, preferLongest) {
 					nextStates = addStateToList(str, idx+1, nextStates, *currentState.next, currentState.threadGroups, nil, preferLongest)