[turbofan] Properly ensure that deoptimization is enabled.

src/compiler/js-native-context-specialization.cc

Index: src/compiler/js-native-context-specialization.cc
diff --git a/src/compiler/js-native-context-specialization.cc b/src/compiler/js-native-context-specialization.cc
index 3c7aacab15ccb4aed449d724f99d9b31c41f0acb..39f88f806fbaf3c6ae50fafa1aa19507a3941524 100644
--- a/src/compiler/js-native-context-specialization.cc
+++ b/src/compiler/js-native-context-specialization.cc
@@ -757,11 +757,13 @@ Reduction JSNativeContextSpecialization::ReduceNamedAccessFromNexus(
   Node* const receiver = NodeProperties::GetValueInput(node, 0);
   Node* const effect = NodeProperties::GetEffectInput(node);
 
-  // Check if we are accessing the current native contexts' global proxy.
-  HeapObjectMatcher m(receiver);
-  if (m.HasValue() && m.Value().is_identical_to(global_proxy())) {
-    // Optimize accesses to the current native contexts' global proxy.
-    return ReduceGlobalAccess(node, nullptr, value, name, access_mode);
+  if (flags() & kDeoptimizationEnabled) {
+    // Check if we are accessing the current native contexts' global proxy.
+    HeapObjectMatcher m(receiver);
+    if (m.HasValue() && m.Value().is_identical_to(global_proxy())) {
+      // Optimize accesses to the current native contexts' global proxy.
+      return ReduceGlobalAccess(node, nullptr, value, name, access_mode);
+    }
   }
 
   // Check if the {nexus} reports type feedback for the IC.