[turbofan] Drop V8_TURBOFAN_BACKEND and V8_TURBOFAN_TARGET defines.

test/cctest/compiler/test-branch-combine.cc

Index: test/cctest/compiler/test-branch-combine.cc
diff --git a/test/cctest/compiler/test-branch-combine.cc b/test/cctest/compiler/test-branch-combine.cc
index 58202a61b0977704c56e1ec5b7ff4ae676a33e32..06d380a6a21928e28e0f247ddfdfad4ab6f2d1de 100644
--- a/test/cctest/compiler/test-branch-combine.cc
+++ b/test/cctest/compiler/test-branch-combine.cc
@@ -8,8 +8,6 @@
 #include "test/cctest/compiler/codegen-tester.h"
 #include "test/cctest/compiler/value-helper.h"
 
-#if V8_TURBOFAN_TARGET
-
 using namespace v8::internal;
 using namespace v8::internal::compiler;
 
@@ -459,4 +457,3 @@ TEST(BranchCombineFloat64Compares) {
     }
   }
 }
-#endif  // V8_TURBOFAN_TARGET