Restore char/varchar predicate pushdown in DomainTranslator

These days, CHAR values coerce to VARCHAR for a predicate a_char = 'varchar constant' the DomainTranslator should construct a Domain on the char column. Perhaps, it could use SATURATED_FLOOR_CAST mechanism for that.

Currently this is blocked by this piece of code https://github.com/trinodb/trino/blob/1847264445869f8e2dbaf03ee2878d4d27dd56f1/core/trino-main/src/main/java/io/trino/sql/planner/DomainTranslator.java#L524-L529

(which is incorrect https://github.com/trinodb/trino/pull/29939/changes#r3802693915)

relates to

• https://github.com/trinodb/trino/issues/30778