[turbofan] Specialize loads of the native context.

src/compiler/node-properties.cc

Index: src/compiler/node-properties.cc
diff --git a/src/compiler/node-properties.cc b/src/compiler/node-properties.cc
index 90ffef30ee5fed5c23d8a74faaefb6c0b258e555..ac9cc34dd9cd1ac577bf2bdf455e4c6fe3ff1d6a 100644
--- a/src/compiler/node-properties.cc
+++ b/src/compiler/node-properties.cc
@@ -4,6 +4,7 @@
 
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
+#include "src/compiler/js-operator.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node-properties.h"
 #include "src/compiler/operator-properties.h"
@@ -335,6 +336,16 @@ MaybeHandle<Context> NodeProperties::GetSpecializationNativeContext(
     Node* node, MaybeHandle<Context> native_context) {
   while (true) {
     switch (node->opcode()) {
+      case IrOpcode::kJSLoadContext: {
+        ContextAccess const& access = ContextAccessOf(node->op());
+        if (access.index() != Context::NATIVE_CONTEXT_INDEX) {
+          return MaybeHandle<Context>();
+        }
+        // Skip over the intermediate contexts, we're only interested in the
+        // very last context in the context chain anyway.
+        node = NodeProperties::GetContextInput(node);
+        break;
+      }
       case IrOpcode::kJSCreateBlockContext:
       case IrOpcode::kJSCreateCatchContext:
       case IrOpcode::kJSCreateFunctionContext: