JDBC H2, `CHAR(10)` column read as `Char?` instead of `String?`

[Jolanrensen]

@zaleslaw
From an H2 database, a CHAR(10) column is read as Char? instead of String?

This issue can be reproduced easily by editing the fun `read from huge table`() in h2Test.kt by adding the line:
schema.columns["characterCol"]!!.type shouldBe typeOf<String?>()
The column contains ["ABC", "DEF", "GHI"] so I gotta agree it's not supposed to be a Char.

I discovered it by exploring whether the DataColumnImpl.type actually matches the types found in DataColumnImpl.values, which mismatches in this case. It might be a good check to do for all type conversions :).