clp-s: Support ? to match single character in searches against variable value columns

[gibber9809]

Request

Currently clp-s supports using wildcards to search against variable value columns, but not ? to match a single character. Since this is supported on the log text search path the resulting behaviour is unintuitive.

Possible implementation

The issue is that for this type of query we only enter into the wildcard search path if the predicate contains '*', ignoring ? characters and escaping rules. We need to add some preprocessing along the variable value column search path to match the behaviour of the log text search path.

[wraymo]

Our log-text behaviour is to treat ? as *, do we want the same thing?

[kirkrodrigues]

For clp-text/clp, that logic is a bit buggy (one issue is #243) but the intent was that we perform a wildcard match with the original query (including ?) just after we decompress a message. For clp-json/clp-s, I would say we should treat ? as matching any single character, as intended. We'll fix clp separately.