Move LookupResult into crankshaft as that's now the only place where it's still used

test/cctest/test-api.cc

Index: test/cctest/test-api.cc
diff --git a/test/cctest/test-api.cc b/test/cctest/test-api.cc
index 5b11386d47c72f0bae3d5857b1e1996a139ace95..c5a79362146fb9cfdd439151b96189d89f24dcc3 100644
--- a/test/cctest/test-api.cc
+++ b/test/cctest/test-api.cc
@@ -1937,8 +1937,6 @@ THREADED_TEST(ExecutableAccessorIsPreservedOnAttributeChange) {
   CompileRun("Object.defineProperty(a, 'length', { writable: false });");
   CHECK_EQ(i::FixedArray::cast(a->map()->instance_descriptors())->length(), 0);
   // But we should still have an ExecutableAccessorInfo.
-  i::Isolate* i_isolate = reinterpret_cast<i::Isolate*>(isolate);
-  i::LookupResult lookup(i_isolate);
   i::Handle<i::String> name(v8::Utils::OpenHandle(*v8_str("length")));
   i::LookupIterator it(a, name, i::LookupIterator::OWN_SKIP_INTERCEPTOR);
   CHECK_EQ(i::LookupIterator::ACCESSOR, it.state());