HIVE-28910: Remove redundant IS NOT NULL predicates when expanding SEARCH

[zabetak]

Does this PR introduce any user-facing change?

Better plans

How was this patch tested?

Existing tests

[sonarqubecloud[bot]]

Quality Gate passed

Issues
9 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[zabetak]

I added two commits to sync with master and resolve conflicts. If it comes green I will merge the PR tomorrow.

[sonarqubecloud[bot]]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[zabetak]

Thanks for the reviews @kasakrisz and @asolimando !