Revert "Introduce MoveDouble to the X64 MacroAssembler" (r17383)

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 c3fd782e54c073d4971280e7ea8a397b98281e87..42245aa80807431aca738a1d12868b6a99bf0057 100644
--- a/src/x64/macro-assembler-x64.h
+++ b/src/x64/macro-assembler-x64.h
@@ -841,9 +841,6 @@ class MacroAssembler: public Assembler {
   void Pop(Register dst) { pop(dst); }
   void PushReturnAddressFrom(Register src) { push(src); }
   void PopReturnAddressTo(Register dst) { pop(dst); }
-  void MoveDouble(Register dst, const Operand& src) { movq(dst, src); }
-  void MoveDouble(const Operand& dst, Register src) { movq(dst, src); }
-
   void Move(Register dst, ExternalReference ext) {
     movp(dst, reinterpret_cast<Address>(ext.address()),
          RelocInfo::EXTERNAL_REFERENCE);