Details:
- Limit the queries to character sets and collations
which are most probably available in all build types.
But try to preserve the intention of the tests.
- Remove the variants adjusted to some build types.
Note:
1. The results of the review by Bar are included.
2. I am not able to check the correctness of this patch
on any existing build type and any MySQL version.
So it could happen that the new test fails somewhere.
