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

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
diff --git a/src/arm/lithium-arm.h b/src/arm/lithium-arm.h
index 0f999c5324d4db86c540997574ed4a7647325366..eea9ece5ae71a3391d84799821a33868b5418a0c 100644
--- a/src/arm/lithium-arm.h
+++ b/src/arm/lithium-arm.h
@@ -1647,15 +1647,9 @@ class LLoadKeyed final : public LTemplateInstruction<1, 2, 0> {
   ElementsKind elements_kind() const {
     return hydrogen()->elements_kind();
   }
-  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();
-  }
 
   DECLARE_CONCRETE_INSTRUCTION(LoadKeyed, "load-keyed")
   DECLARE_HYDROGEN_ACCESSOR(LoadKeyed)
@@ -2253,13 +2247,9 @@ 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]; }