[code-stubs] Add LoadMapElementsKind helper

src/code-stub-assembler.h

Index: src/code-stub-assembler.h
diff --git a/src/code-stub-assembler.h b/src/code-stub-assembler.h
index 5f42d2920eab6b905604a5f8e8469559405b82cf..d3d4e6a2c3e80ad134ad08dd4c92402a246efdf4 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -235,6 +235,8 @@ class CodeStubAssembler : public compiler::CodeAssembler {
   compiler::Node* LoadMapBitField3(compiler::Node* map);
   // Load the instance type of a map.
   compiler::Node* LoadMapInstanceType(compiler::Node* map);
+  // Load the ElementsKind of a map.
+  compiler::Node* LoadMapElementsKind(compiler::Node* map);
   // Load the instance descriptors of a map.
   compiler::Node* LoadMapDescriptors(compiler::Node* map);
   // Load the prototype of a map.