Config double register number as 1 for X87 Turbofan.

src/arm/assembler-arm.h

Index: src/arm/assembler-arm.h
diff --git a/src/arm/assembler-arm.h b/src/arm/assembler-arm.h
index 82d786fe512b2ba98844df9793ca89d3f361ef8b..7608600773b1cba15b8de53de52e269706aef5ea 100644
--- a/src/arm/assembler-arm.h
+++ b/src/arm/assembler-arm.h
@@ -223,6 +223,14 @@ struct DwVfpRegister {
   // registers on ARM.
   inline static int NumAllocatableAliasedRegisters();
 
+  static int NumAllocatableRegistersForTurbo() {
+    return kMaxNumAllocatableRegisters;
+  }
+
+  static int NumAllocatableAliasedRegistersForTurbo() {
+    return NumAllocatableAliasedRegisters();
+  }
+
   inline static int ToAllocationIndex(DwVfpRegister reg);
   static const char* AllocationIndexToString(int index);
   inline static DwVfpRegister FromAllocationIndex(int index);