devices: bus: add busrange cmp/clone tests & enhance bus_insert test
devices: bus: add busrange cmp/clone tests & enhance bus_insert test

Add busrange tests for verifying busrange operations and modify the
bus_insert test to check also the formatted error string.

Signed-off-by: Constantin Musca <e6b0bba089ab6d3e8fde8b62faae63e6b21d7743@amazon.com>

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