* Remove qiskit-toqm tests and requirements-dev.txt entry

Im #9042 we removed the special case code to enable using toqm as an
optional routing method. This was needed prior to qiskit-terra 0.22.0 as
we didn't have the transpiler stage plugin interface. However, now that
we've added a dedicated interface for external transpiler passes to
integrate into transpile() the toqm passes are using that interface.
However, in #9042 the tests for verifying the previously hard-coded toqm
routing method path worked as before were left intact. In general this
would be a good approach to ensure we're maintaining backwards
compatibilty with the new modular interface with earlier releases.
However, in this specific case this is causing an issue with how tests
are run. Since qiskit-toqm has a necessary dependency on qiskit-terra
this means when we install our development requirements before running
tests toqm is pulling in the latest stable release of qiskit-terra from
pypi. Then we later upgrade that with the source build before running
tests. This however this bi-directional test dependency introduces a
tension in a number of places. For the most recent example, when we're
trying to add support for new platforms (see #9028 for an example)
where the stable version of qiskit-terra does not support the platform.
We're unable to run CI with qiskit-toqm being installed first since
installing stable qiskit-terra won't work/

This commit removes qiskit-toqm from the requirements-dev.txt list and
also removes the test cases using it to fix this conflict. In general
the testing for qiskit-toqm can now be self contained since it's
exercising a stable interface in terra that's tested independently. When
weighing the backwards compatibility coverage vs the CI and build
complexities having the bidirectional test dependency has just removing
the toqm tests and development requirement is the simplest path forward.

* Remove unused imports

Co-authored-by: mergify[bot] <37929162+mergify[bot]@users.noreply.github.com>
(cherry picked from commit 8999047)

# Conflicts:
#	requirements-dev.txt

This fixes a merge conflict and removes the qiskit-toqm entry from the requirements-dev.txt file