[turbofan] Enforce native context specialization.

test/unittests/compiler/graph-unittest.h

Index: test/unittests/compiler/graph-unittest.h
diff --git a/test/unittests/compiler/graph-unittest.h b/test/unittests/compiler/graph-unittest.h
index d4248e422b31c073f0bf5bfab1fbd95e8df2a0fb..2542e68a91d81a6a6f2204918412b340c99eae6f 100644
--- a/test/unittests/compiler/graph-unittest.h
+++ b/test/unittests/compiler/graph-unittest.h
@@ -23,8 +23,8 @@ namespace compiler {
 
 using ::testing::Matcher;
 
-
-class GraphTest : public TestWithContext, public TestWithIsolateAndZone {
+class GraphTest : public virtual TestWithNativeContext,
+                  public virtual TestWithIsolateAndZone {
  public:
   explicit GraphTest(int num_parameters = 1);
   ~GraphTest() override;