fix: freeze unhashable args in Query.test to prevent TypeError

[gaoflow]

Problem

Passing a list or dict as an extra argument to Query().field.test() raises
TypeError: unhashable type: 'list' (or 'dict') the first time TinyDB tries
to hash the resulting QueryInstance for the query cache.

def in_set(val, allowed):
    return val in allowed

db.search(Query().x.test(in_set, [1, 2, 3]))  # TypeError: unhashable type: 'list'

Reported in #514 (issue #517).

Root cause

Query.test builds its cache key tuple as:

('test', self._path, func, args)

args is a raw Python tuple that can contain unhashable objects (list,
dict). Every other query method that accepts caller-supplied values
(any, all, one_of, fragment) already passes them through the
existing freeze() helper before building the hash tuple. test was
the only method that did not.

Fix

Apply freeze() to each element of args before composing the hash
tuple, matching the pattern used by the sibling methods:

('test', self._path, func, tuple(freeze(arg) for arg in args))

freeze() recursively converts list → tuple, dict → FrozenDict,
and set → frozenset, so nested unhashable structures are handled too.
The test function still receives the original (unfrozen) args at
call-time; only the hash key is affected.

Tests

Added test_custom_with_unhashable_params in tests/test_queries.py
covering list args, dict args, same-args hash stability, and different-args
hash distinctness.