[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

test/cctest/compiler/test-linkage.cc

Index: test/cctest/compiler/test-linkage.cc
diff --git a/test/cctest/compiler/test-linkage.cc b/test/cctest/compiler/test-linkage.cc
index cbfde03ca665e75e1ea69dc050b0617a56e7dd10..29da5890eaf476cf7db66171b77a18e99516e01f 100644
--- a/test/cctest/compiler/test-linkage.cc
+++ b/test/cctest/compiler/test-linkage.cc
@@ -19,8 +19,6 @@
 #include "src/compiler/schedule.h"
 #include "test/cctest/cctest.h"
 
-#if V8_TURBOFAN_TARGET
-
 using namespace v8::internal;
 using namespace v8::internal::compiler;
 
@@ -113,5 +111,3 @@ TEST(TestLinkageRuntimeCall) {
 TEST(TestLinkageStubCall) {
   // TODO(titzer): test linkage creation for outgoing stub calls.
 }
-
-#endif  // V8_TURBOFAN_TARGET