Treat FOREIGN_TYPE as internal.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/257523002

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@20920 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/types.cc

@@ -256,6 +256,7 @@ int TypeImpl<Config>::BitsetType::Lub(i::Map* map) {
     case EXECUTABLE_ACCESSOR_INFO_TYPE:
     case ACCESSOR_PAIR_TYPE:
     case FIXED_ARRAY_TYPE:
+    case FOREIGN_TYPE:
       return kInternal & kTaggedPtr;
     default:
       UNREACHABLE();