We should have a test case which requires non-flat physical hierarchy in MPL

[AcKoucher]

Description

Currently, all of our test cases use flat physical hierarchy so we are not benefiting from HierRTLMP as we could.

Suggested Solution

Maybe some large private design can be used.

Additional Context

This is more of an ORFS issue, but I'm opening as an OR issue in order to be able to use the issues' relationship.