Current testing technique does not catch some cases when the return value is not valid for given type

[findepi]

io.prestosql.sql.query.QueryAssertions#expression(java.lang.String) + matches can pass eveb when value is not correct for given type: eg not properly truncated (char with trailing spaces), or not properly rounded (timestamp with not max precision).

See #5736 (comment) for example.

Implementation plan:

Add checks within (explicitly or implicitly) io.prestosql.spi.type.Type#getObjectValue implementations:

• decimal scale, precision checks
• char length check, padding spaces stripped check Add char, varchar wellformedness checks #5743
• varchar length check Add char, varchar wellformedness checks #5743
• time and time with time zone precision checks
• timestamp and timestamp with time zone precision checks Fix rounding in cast from TIME to TIMESTAMP #5742 (ba17097)

[findepi]

I updated the description with the checklist. @prestosql/maintainers please update if any more checks we should add come to your mind.

[findepi]

We still need to add checks for decimal.
So far @ksobolew added a check flagging "negative zero", but we also need precision/scale checks.

cc @ksobolew @lukasz-stec