DM-34862, the tests in obs_decam can be migrated from gen2 to gen3.
These tests should use the SimplePipelineExecutor to do calibration lookups and exercise basic ISR functionality including crosstalk. The current nopytest_test_processCcd.py is slow (it goes all the way to calexp) and mostly unnecessary and will be removed. Within that test file is testWcsPostIsr which is essential to maintain. This ticket will create a new test_isr.py which will replace test_crosstalk.py and include the necessary crosstalk and wcs (and any other tests that require decam ISR).
Other tests that touch gen2-only features (like testing mappers) will be removed, and tests will be migrated to gen3 as appropriate.