provides a mechanism for optimizing compilers to select the different Register configuration.

test/cctest/test-code-stubs-x64.cc

Index: test/cctest/test-code-stubs-x64.cc
diff --git a/test/cctest/test-code-stubs-x64.cc b/test/cctest/test-code-stubs-x64.cc
index 9245d9d0852cfe4a10b096a1eb3c8133922620d3..31c8a134ea5af65ccfbfcafbfd324c775378eea7 100644
--- a/test/cctest/test-code-stubs-x64.cc
+++ b/test/cctest/test-code-stubs-x64.cc
@@ -64,7 +64,8 @@ ConvertDToIFunc MakeConvertDToIFuncTrampoline(Isolate* isolate,
   __ pushq(rdi);
 
 
-  const RegisterConfiguration* config = RegisterConfiguration::ArchDefault();
+  const RegisterConfiguration* config =
+      RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT);
   if (!source_reg.is(rsp)) {
     // The argument we pass to the stub is not a heap number, but instead
     // stack-allocated and offset-wise made to look like a heap number for