Eliminate special keyed load string stub in favor of uniform handlers.

src/ic/arm64/ic-arm64.cc

Index: src/ic/arm64/ic-arm64.cc
diff --git a/src/ic/arm64/ic-arm64.cc b/src/ic/arm64/ic-arm64.cc
index 76f9c24cf161285b8caf58fc40d43490fa96cd70..dc419f0334cd64a00bc735f0eed543f57a333003 100644
--- a/src/ic/arm64/ic-arm64.cc
+++ b/src/ic/arm64/ic-arm64.cc
@@ -627,32 +627,6 @@ void KeyedLoadIC::GenerateGeneric(MacroAssembler* masm) {
 }
 
 
-void KeyedLoadIC::GenerateString(MacroAssembler* masm) {
-  // Return address is in lr.
-  Label miss;
-
-  Register receiver = LoadDescriptor::ReceiverRegister();
-  Register index = LoadDescriptor::NameRegister();
-  Register result = x0;
-  Register scratch = x3;
-  DCHECK(!scratch.is(receiver) && !scratch.is(index));
-
-  StringCharAtGenerator char_at_generator(receiver, index, scratch, result,
-                                          &miss,  // When not a string.
-                                          &miss,  // When not a number.
-                                          &miss,  // When index out of range.
-                                          STRING_INDEX_IS_ARRAY_INDEX);
-  char_at_generator.GenerateFast(masm);
-  __ Ret();
-
-  StubRuntimeCallHelper call_helper;
-  char_at_generator.GenerateSlow(masm, call_helper);
-
-  __ Bind(&miss);
-  GenerateMiss(masm);
-}
-
-
 void KeyedStoreIC::GenerateMiss(MacroAssembler* masm) {
   ASM_LOCATION("KeyedStoreIC::GenerateMiss");