Fix MIPS build: use stubbed-out TF implementation

test/cctest/compiler/test-instruction-selector.cc

Index: test/cctest/compiler/test-instruction-selector.cc
diff --git a/test/cctest/compiler/test-instruction-selector.cc b/test/cctest/compiler/test-instruction-selector.cc
index 20ca5a5ea3e215dbc4711b6ddc17fd5883737fe8..862643f0c8f4b42dbc42a214b6abbf1134df0308 100644
--- a/test/cctest/compiler/test-instruction-selector.cc
+++ b/test/cctest/compiler/test-instruction-selector.cc
@@ -7,6 +7,8 @@
 using namespace v8::internal;
 using namespace v8::internal::compiler;
 
+#if V8_TURBOFAN_TARGET
+
 TEST(InstructionSelectionReturnZero) {
   InstructionSelectorTester m(InstructionSelectorTester::kInternalMode);
   m.Return(m.Int32Constant(0));
@@ -16,3 +18,5 @@ TEST(InstructionSelectionReturnZero) {
   CHECK_EQ(kArchRet, m.code[1]->opcode());
   CHECK_EQ(1, static_cast<int>(m.code[1]->InputCount()));
 }
+
+#endif