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

src/isolate.h

Index: src/isolate.h
diff --git a/src/isolate.h b/src/isolate.h
index 35443d79dd51c1c1430a6aea0cc5feecd012b0b2..fdd183288897f4721d8aa96b5435db48b2a73b95 100644
--- a/src/isolate.h
+++ b/src/isolate.h
@@ -313,9 +313,6 @@ class ThreadLocalTop BASE_EMBEDDED {
   // Call back function to report unsafe JS accesses.
   v8::FailedAccessCheckCallback failed_access_check_callback_;
 
-  // Head of the list of live LookupResults.
-  LookupResult* top_lookup_result_;
-
  private:
   void InitializeInternal();
 
@@ -1008,8 +1005,6 @@ class Isolate {
     return embedder_data_[slot];
   }
 
-  THREAD_LOCAL_TOP_ACCESSOR(LookupResult*, top_lookup_result)
-
   bool serializer_enabled() const { return serializer_enabled_; }
 
   bool IsDead() { return has_fatal_error_; }