`libdispatch_queue` is missing customizations for `bulk_chunked` and `bulk_unchunked`

[ericniebler]

[alwaysprince05]

PR #2227 added the missing bulk_chunked and bulk_unchunked customizations for libdispatch_queue (merged as 9b278f8) along with test coverage in test_libdispatch.cpp. Both customizations are present in current main, so this can be closed.