Explicitly clear type map before run `test_only_reload_type_map_once_for_every_unknown_type`

Currently, the following test fails.

```
bin/test -a sqlite3_mem --seed 37473 test/cases/relation_test.rb
```

This is due to reset connection in `test_respond_to_for_non_selected_element` postprocessing.
This reset is added with #29332 for `test_only_reload_type_map_once_for_every_unknown_type`.

Since the above test expects the type map to be empty at the time of
test run, I think that it is better to empty the type map before test run.

0 files changed, 0 insertions, 0 deletions