X64: Load HeapNumberMap once in BinaryOpStub, and reuse it.

src/x64/macro-assembler-x64.h

Index: src/x64/macro-assembler-x64.h
diff --git a/src/x64/macro-assembler-x64.h b/src/x64/macro-assembler-x64.h
index 1c6b6477be9c295b41171f42a2514f6f886a9996..bb0b68105b67c715e3366027b9ffb4aa70272edd 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -556,6 +556,11 @@ class MacroAssembler: public Assembler {
   // Abort execution if argument is not a smi. Used in debug code.
   void AbortIfNotSmi(Register object);
 
+  // Abort execution if argument is not the root value with the given index.
+  void AbortIfNotRootValue(Register src,
+                           Heap::RootListIndex root_value_index,
+                           const char* message);
+
   // ---------------------------------------------------------------------------
   // Exception handling