Config double register number as 1 for X87 Turbofan.

src/mips/assembler-mips.h

Index: src/mips/assembler-mips.h
diff --git a/src/mips/assembler-mips.h b/src/mips/assembler-mips.h
index c116c13bcddfc746f8c2473fa4ce98e3ea6dd0e4..f7efdfeeae46ff3a3215543ffbc6e67f28c0a253 100644
--- a/src/mips/assembler-mips.h
+++ b/src/mips/assembler-mips.h
@@ -228,6 +228,14 @@ struct FPURegister {
   // TODO(turbofan): Proper support for float32.
   inline static int NumAllocatableAliasedRegisters();
 
+  static int NumAllocatableRegistersForTurbo() {
+    return kMaxNumAllocatableRegisters;
+  }
+
+  static int NumAllocatableAliasedRegistersForTurbo() {
+    return NumAllocatableAliasedRegisters();
+  }
+
   inline static int ToAllocationIndex(FPURegister reg);
   static const char* AllocationIndexToString(int index);