Improve performance of delete+insert incremental strategy with null equality check changes

[adrianburusdbt]

This PR merges the changes for null equality from here: #744 into existing PR: #151

resolves #150
resolves #364

Problem

Solution

Checklist

• I have read the contributing guide and understand what's expected of me
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• This PR has no interface changes (e.g. macros, cli, logs, json artifacts, config files, adapter interface, etc) or this PR has already received feedback and approval from Product or DX

[VanTudor]

Code lgtm, but let's address those failing tests

[VersusFacit]

Researched the implications and tests passing. This is judged to be functionally equivalent to the original macro, the performance benefits notwithstanding.

[jhsb25]

any ideas when this will be available, delete+insert are painfully slow currently

[VersusFacit]

@jhsb25 should hit Cloud in about a week upper bound, two weeks OSS at current pace unless we had some rollbacks for some reason