[runtime] Object.create(null) creates a slow object

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 ae05a6c5294a26a39cf65f5b35fb57712209c0bd..c5bcd1f8f0e19a394dacf13a8bdbb02c0af0b60a 100644
--- a/src/code-stub-assembler.h
+++ b/src/code-stub-assembler.h
@@ -108,6 +108,8 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                                          compiler::Node* right);
   compiler::Node* IntPtrSubFoldConstants(compiler::Node* left,
                                          compiler::Node* right);
+  void BranchIfWordIsPowerOfTwo(compiler::Node* value, Label* if_true,
+                                Label* if_false);
 
   // Float64 operations.
   compiler::Node* Float64Ceil(compiler::Node* x);
@@ -431,6 +433,9 @@ class V8_EXPORT_PRIVATE CodeStubAssembler : public compiler::CodeAssembler {
                                        compiler::Node* index,
                                        compiler::Node* input);
 
+  compiler::Node* AllocateNameDictionary(int capacity);
+  compiler::Node* AllocateNameDictionary(compiler::Node* capacity);
+
   compiler::Node* AllocateJSObjectFromMap(compiler::Node* map,
                                           compiler::Node* properties = nullptr,
                                           compiler::Node* elements = nullptr);