test: show stats in explain of two representative queries

[NGA-TRAN]

Which issue does this PR close?

Tests for https://github.com/apache/arrow-datafusion/issues/8155

Rationale for this change

I have found that statistics were lost being propagated upward in the plan. These are tests that include representative operators for us to verify whether the statistics are computed and propagated up correctly

What changes are included in this PR?

Add 2 explains

Are these changes tested?

They are tests only

Are there any user-facing changes?

No