message: Remove an outdated comment in create_metadata_tables.
  The underlying issue turned out to be a bug in `memmove` on some Android
  devices. It was addressed via
diff: @@ -55,11 +55,6 @@ const size_t c_zeroRowIndex = 0;
  const char c_object_table_prefix[] = "class_";
  void create_metadata_tables(Group& group) {
  - // FIXME: the order of the creation of the two tables seems to
  - // matter for some Android devices. The reason is unclear, and
  - // further investigation is required.
  - // See https://github.com/realm/realm-java/issues/3651
  -
  // The tables 'pk' and 'metadata' are treated specially by Sync. The 'pk' table
  // is populated by `sync::create_table` and friends, while the 'metadata' table
  // is simply ignored.
  