TEXT_CONTAINS does not match results where argument is in upper case

Let's say you have the following data, and you've added a native index on `col1`.
```
col1
'A V1'
'A'
```

TEXT_CONTAINS("col1", 'A') will return FALSE for both rows, which is unexpected.. TEXT_CONTAINS("col1", 'a') returns TRUE for both rows.

Reproduce TEXT_CONTAINS("col1", 'A') against a native index using the two rows described in the issue, then trace the TEXT_CONTAINS implementation and its related tests. Done means uppercase and lowercase arguments produce the expected matches for both rows, with a regression test covering the case.

Written by the indexing model from the issue text.