Revert of [turbofan] Various fixes to allow unboxed doubles as arguments in registers...

test/cctest/compiler/c-signature.h

Index: test/cctest/compiler/c-signature.h
diff --git a/test/cctest/compiler/c-signature.h b/test/cctest/compiler/c-signature.h
index 8eaf6325f22011081d6a6a957440c66aae44248d..83b3328a3b4e256274f7a2c898fee26d42825dd7 100644
--- a/test/cctest/compiler/c-signature.h
+++ b/test/cctest/compiler/c-signature.h
@@ -67,10 +67,6 @@
         CHECK_EQ(kMachNone, params[p]);
       }
     }
-  }
-
-  static CSignature* FromMachine(Zone* zone, MachineSignature* msig) {
-    return reinterpret_cast<CSignature*>(msig);
   }
 
   static CSignature* New(Zone* zone, MachineType ret,