assert: fix deepEqual inconsistencies

Fixes #14441 (closed)

I moved some tests over to assert-deep as they now always test all variations and it makes more sense to keep the deep-equal tests in there anyway.

Note: the original test added in #13318 was actually faulty.

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

assert