[runtime] Kill the %NumberToIntegerMapMinusZero runtime entry.

src/arm64/code-stubs-arm64.cc

Index: src/arm64/code-stubs-arm64.cc
diff --git a/src/arm64/code-stubs-arm64.cc b/src/arm64/code-stubs-arm64.cc
index d55d2c1a524c5ee223907d90ccbd2127061d1941..576b1c7fbde1b072644daffa62cb0de3be88e1de 100644
--- a/src/arm64/code-stubs-arm64.cc
+++ b/src/arm64/code-stubs-arm64.cc
@@ -1478,7 +1478,6 @@ void LoadIndexedStringStub::Generate(MacroAssembler* masm) {
                                           &miss,  // When not a string.
                                           &miss,  // When not a number.
                                           &miss,  // When index out of range.
-                                          STRING_INDEX_IS_ARRAY_INDEX,
                                           RECEIVER_IS_STRING);
   char_at_generator.GenerateFast(masm);
   __ Ret();
@@ -2403,13 +2402,7 @@ void StringCharCodeAtGenerator::GenerateSlow(
     // Save object_ on the stack and pass index_ as argument for runtime call.
     __ Push(object_, index_);
   }
-  if (index_flags_ == STRING_INDEX_IS_NUMBER) {
-    __ CallRuntime(Runtime::kNumberToIntegerMapMinusZero);
-  } else {
-    DCHECK(index_flags_ == STRING_INDEX_IS_ARRAY_INDEX);
-    // NumberToSmi discards numbers that are not exact integers.
-    __ CallRuntime(Runtime::kNumberToSmi);
-  }
+  __ CallRuntime(Runtime::kNumberToSmi);
   // Save the conversion result before the pop instructions below
   // have a chance to overwrite it.
   __ Mov(index_, x0);
@@ -3095,7 +3088,7 @@ void SubStringStub::Generate(MacroAssembler* masm) {
   __ SmiTag(from);
   StringCharAtGenerator generator(input_string, from, result_length, x0,
                                   &runtime, &runtime, &runtime,
-                                  STRING_INDEX_IS_NUMBER, RECEIVER_IS_STRING);
+                                  RECEIVER_IS_STRING);
   generator.GenerateFast(masm);
   __ Drop(3);
   __ Ret();