Revert of [turbofan] inline %StringIteratorPrototype%.next in JSBuiltinReducer.

src/compiler/simplified-operator.cc

Index: src/compiler/simplified-operator.cc
diff --git a/src/compiler/simplified-operator.cc b/src/compiler/simplified-operator.cc
index a7bbae3493ce70fc555291f8a4c8f7a3e0f11282..b7b230fc7b25ce02595684639a0bae1fc08aea49 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -334,11 +334,6 @@
 PretenureFlag PretenureFlagOf(const Operator* op) {
   DCHECK_EQ(IrOpcode::kAllocate, op->opcode());
   return OpParameter<PretenureFlag>(op);
-}
-
-UnicodeEncoding UnicodeEncodingOf(const Operator* op) {
-  DCHECK(op->opcode() == IrOpcode::kStringFromCodePoint);
-  return OpParameter<UnicodeEncoding>(op);
 }
 
 #define PURE_OP_LIST(V)                                          \
@@ -473,17 +468,6 @@
   CHECKED_OP_LIST(CHECKED)
 #undef CHECKED
 
-  template <UnicodeEncoding kEncoding>
-  struct StringFromCodePointOperator final : public Operator {
-    StringFromCodePointOperator()
-        : Operator(IrOpcode::kStringFromCodePoint, Operator::kPure,
-                   "StringFromCodePoint", 1, 0, 0, 1, 0, 0) {}
-  };
-  StringFromCodePointOperator<UnicodeEncoding::UTF16>
-      kStringFromCodePointOperatorUTF16;
-  StringFromCodePointOperator<UnicodeEncoding::UTF32>
-      kStringFromCodePointOperatorUTF32;
-
   struct ArrayBufferWasNeuteredOperator final : public Operator {
     ArrayBufferWasNeuteredOperator()
         : Operator(IrOpcode::kArrayBufferWasNeutered, Operator::kEliminatable,
@@ -770,18 +754,6 @@
   return nullptr;
 }
 
-const Operator* SimplifiedOperatorBuilder::StringFromCodePoint(
-    UnicodeEncoding encoding) {
-  switch (encoding) {
-    case UnicodeEncoding::UTF16:
-      return &cache_.kStringFromCodePointOperatorUTF16;
-    case UnicodeEncoding::UTF32:
-      return &cache_.kStringFromCodePointOperatorUTF32;
-  }
-  UNREACHABLE();
-  return nullptr;
-}
-
 #define SPECULATIVE_NUMBER_BINOP(Name)                                        \
   const Operator* SimplifiedOperatorBuilder::Name(NumberOperationHint hint) { \
     switch (hint) {                                                           \