Revert of Remove register index/code indirection

src/deoptimizer.cc

Index: src/deoptimizer.cc
diff --git a/src/deoptimizer.cc b/src/deoptimizer.cc
index 786a46640e758cd1a37399b11744db483c33a595..b1f1576081153338d2359f47a10eb8c2c07e3c69 100644
--- a/src/deoptimizer.cc
+++ b/src/deoptimizer.cc
@@ -2072,7 +2072,7 @@
 
 void Translation::StoreDoubleRegister(DoubleRegister reg) {
   buffer_->Add(DOUBLE_REGISTER, zone());
-  buffer_->Add(reg.code(), zone());
+  buffer_->Add(DoubleRegister::ToAllocationIndex(reg), zone());
 }
 
 
@@ -2925,7 +2925,7 @@
       double value = registers->GetDoubleRegister(input_reg);
       if (trace_file != nullptr) {
         PrintF(trace_file, "%e ; %s (bool)", value,
-               DoubleRegister::from_code(input_reg).ToString());
+               DoubleRegister::AllocationIndexToString(input_reg));
       }
       return TranslatedValue::NewDouble(this, value);
     }