[RegisterConfiguration] Streamline access to arch defaults, simplify Registers.

src/s390/deoptimizer-s390.cc

Index: src/s390/deoptimizer-s390.cc
diff --git a/src/s390/deoptimizer-s390.cc b/src/s390/deoptimizer-s390.cc
index 44062d6e79f78ca165bf2d29ba742a7c244196f5..6ee8c742130c6d1519cf6fd7832fc2f096913fa2 100644
--- a/src/s390/deoptimizer-s390.cc
+++ b/src/s390/deoptimizer-s390.cc
@@ -116,8 +116,7 @@ void Deoptimizer::TableEntryGenerator::Generate() {
 
   // Save all double registers before messing with them.
   __ lay(sp, MemOperand(sp, -kDoubleRegsSize));
-  const RegisterConfiguration* config =
-      RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT);
+  const RegisterConfiguration* config = RegisterConfiguration::Crankshaft();
   for (int i = 0; i < config->num_allocatable_double_registers(); ++i) {
     int code = config->GetAllocatableDoubleCode(i);
     const DoubleRegister dreg = DoubleRegister::from_code(code);