Reland of "Remove ExternalArray, derived types, and element kinds"

src/x64/lithium-x64.h

Index: src/x64/lithium-x64.h
diff --git a/src/x64/lithium-x64.h b/src/x64/lithium-x64.h
index cd51a4d76391be4df258524f6f2a00b9a7029461..2ba248642c14b21f6ca0d7e8ba5077b931a45f03 100644
--- a/src/x64/lithium-x64.h
+++ b/src/x64/lithium-x64.h
@@ -1617,12 +1617,8 @@ inline static bool ExternalArrayOpRequiresTemp(
   // an index cannot fold the scale operation into a load and need an extra
   // temp register to do the work.
   return SmiValuesAre31Bits() && key_representation.IsSmi() &&
-      (elements_kind == EXTERNAL_INT8_ELEMENTS ||
-       elements_kind == EXTERNAL_UINT8_ELEMENTS ||
-       elements_kind == EXTERNAL_UINT8_CLAMPED_ELEMENTS ||
-       elements_kind == UINT8_ELEMENTS ||
-       elements_kind == INT8_ELEMENTS ||
-       elements_kind == UINT8_CLAMPED_ELEMENTS);
+         (elements_kind == UINT8_ELEMENTS || elements_kind == INT8_ELEMENTS ||
+          elements_kind == UINT8_CLAMPED_ELEMENTS);
 }
 
 
@@ -1636,15 +1632,9 @@ class LLoadKeyed final : public LTemplateInstruction<1, 2, 0> {
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed, "load-keyed")
   DECLARE_HYDROGEN_ACCESSOR(LoadKeyed)
 
-  bool is_external() const {
-    return hydrogen()->is_external();
-  }
   bool is_fixed_typed_array() const {
     return hydrogen()->is_fixed_typed_array();
   }
-  bool is_typed_elements() const {
-    return is_external() || is_fixed_typed_array();
-  }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   void PrintDataTo(StringStream* stream) override;
@@ -2233,13 +2223,9 @@ class LStoreKeyed final : public LTemplateInstruction<0, 3, 0> {
     inputs_[2] = value;
   }
 
-  bool is_external() const { return hydrogen()->is_external(); }
   bool is_fixed_typed_array() const {
     return hydrogen()->is_fixed_typed_array();
   }
-  bool is_typed_elements() const {
-    return is_external() || is_fixed_typed_array();
-  }
   LOperand* elements() { return inputs_[0]; }
   LOperand* key() { return inputs_[1]; }
   LOperand* value() { return inputs_[2]; }