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

src/x87/deoptimizer-x87.cc

Index: src/x87/deoptimizer-x87.cc
diff --git a/src/x87/deoptimizer-x87.cc b/src/x87/deoptimizer-x87.cc
index 9d4645e782524374e0e4339785f75f12040db1e9..15dabb980850c50e00305e550313633abd2d6851 100644
--- a/src/x87/deoptimizer-x87.cc
+++ b/src/x87/deoptimizer-x87.cc
@@ -277,8 +277,7 @@ void Deoptimizer::TableEntryGenerator::Generate() {
   }
 
   int double_regs_offset = FrameDescription::double_registers_offset();
-  const RegisterConfiguration* config =
-      RegisterConfiguration::ArchDefault(RegisterConfiguration::CRANKSHAFT);
+  const RegisterConfiguration* config = RegisterConfiguration::Crankshaft();
   // Fill in the double input registers.
   for (int i = 0; i < X87Register::kMaxNumAllocatableRegisters; ++i) {
     int code = config->GetAllocatableDoubleCode(i);