Fix PackageSuspensionTest on HSUM

For the coexistence tests, switch to use PO + DMRH
instead of DO + DMRH. This is because on HSUM, the
default DO mode is affiliated which runs on user 0
instead of the instrumented user, different from
where the DMRH runs. PO + DMRH is a better choice
as PO is always running on the same user as DMRH.

Bug: 383278687
Test: PackageSuspensionTest
Flag: EXEMPT test
Change-Id: I4234475f3d6747d573090516912c95fda9f9a93e