Decouple CpuFeatures from serializer state.

src/full-codegen.cc

Index: src/full-codegen.cc
diff --git a/src/full-codegen.cc b/src/full-codegen.cc
index 3a5a6301a8276a409d9514921585a48a1d027b6a..7db8a5680edaf27e49fcff5a3c8239d635951392 100644
--- a/src/full-codegen.cc
+++ b/src/full-codegen.cc
@@ -402,7 +402,7 @@ void FullCodeGenerator::Initialize() {
   // we disable the production of debug code in the full compiler if we are
   // either generating a snapshot or we booted from a snapshot.
   generate_debug_code_ = FLAG_debug_code &&
-                         !Serializer::enabled(isolate()) &&
+                         !masm_->serializer_enabled() &&
                          !Snapshot::HaveASnapshotToStartFrom();
   masm_->set_emit_debug_code(generate_debug_code_);
   masm_->set_predictable_code_size(true);