[compiler] try deleting unlowered TableKeyByAndAggregate

[patrick-schultz]

Change Description

Just an experiment for now...

Security Assessment

• This change cannot impact the Hail Batch instance as deployed by Broad Institute in GCP

[cjllanwarne]

If #15395 merges, the test batch for this PR would only have run the following steps:

[
    'check_hail',
    'compile_hail_213',
    'merge_code',
    'test_batch_invariants',
    'test_hail_java',
    'test_hail_python',
    'test_hail_python_local_backend',
    'test_hail_python_service_backend_gcp',
    'test_hail_python_unchecked_allocator',
    'test_hail_scala_fs',
    'test_hail_services_java',
    'test_hail_spark_conf_requester_pays_parsing',
    'test_hailgenetics_hail_image',
    'test_hailgenetics_hail_image_python_3_10',
    'test_hailgenetics_hail_image_python_3_12',
    'test_hailgenetics_hail_image_python_3_13',
    'test_python_docs',
]