Fix some more SQL set op + PartiQL bag op tests

[alancai98]

Issue #, if available:

• Related to https://github.com/partiql/partiql-lang/issues/76 and https://github.com/partiql/partiql-tests/pull/120
• Same tests changed as https://github.com/partiql/partiql-tests/pull/122

Description of changes:

• Fixes some more PartiQL bag op tests related to https://github.com/partiql/partiql-tests/pull/120. Specifically for strict mode, error when an outer bag op argument is a non-collection
• Also adds some PartiQL bag op parsing tests using ORDER BY, LIMIT, and OFFSET

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[alancai98]

From offline discussion, decided we shall allow for LIMIT, OFFSET, and ORDER BY to be applied to outer bag ops. And also modify the coercion logic for NULL and MISSING (i.e. wrap the absent value in a bag rather than empty bag). I will update the PR to reflect those changes.