Make String.prototype.split honor limit when separator is empty.

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 5534db557ce53faee9c85aed9681749804354619..327114898078769f44d057252b850acc799ac182 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -5020,11 +5020,12 @@ static int CopyCachedAsciiCharsToArray(const char* chars,
 // For example, "foo" => ["f", "o", "o"].
 static MaybeObject* Runtime_StringToArray(Arguments args) {
   HandleScope scope;
-  ASSERT(args.length() == 1);
+  ASSERT(args.length() == 2);
   CONVERT_ARG_CHECKED(String, s, 0);
+  CONVERT_NUMBER_CHECKED(uint32_t, limit, Uint32, args[1]);
 
   s->TryFlatten();
-  const int length = s->length();
+  const int length = static_cast<int>(Min<uint32_t>(s->length(), limit));
 
   Handle<FixedArray> elements;
   if (s->IsFlat() && s->IsAsciiRepresentation()) {