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

src/mips64/lithium-mips64.h

Index: src/mips64/lithium-mips64.h
diff --git a/src/mips64/lithium-mips64.h b/src/mips64/lithium-mips64.h
index ce4037724189999bb49decca6fc6523408799e27..71ce5496ac3dc1b593de969a9e655fa967b101f1 100644
--- a/src/mips64/lithium-mips64.h
+++ b/src/mips64/lithium-mips64.h
@@ -1672,15 +1672,9 @@ 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)
@@ -2262,13 +2256,9 @@ 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]; }