uucore: remove support for Bitrig #3045

Job	Run time
Build the fuzzers	4m 5s
Run the fuzzers (fuzz_test, true)	4m 14s
Run the fuzzers (fuzz_date, false)	4m 13s
Run the fuzzers (fuzz_expr, true)	4m 16s
Run the fuzzers (fuzz_printf, false)	3m 21s
Run the fuzzers (fuzz_echo, true)	4m 12s
Run the fuzzers (fuzz_seq, false)	3m 12s
Run the fuzzers (fuzz_sort, false)	3m 22s
Run the fuzzers (fuzz_wc, false)	3m 45s
Run the fuzzers (fuzz_cut, false)	3m 11s
Run the fuzzers (fuzz_split, false)	3m 29s
Run the fuzzers (fuzz_tr, false)	3m 25s
Run the fuzzers (fuzz_env, false)	3m 5s
Run the fuzzers (fuzz_parse_glob, true)	4m 5s
Run the fuzzers (fuzz_parse_size, true)	4m 2s
Run the fuzzers (fuzz_parse_time, true)	4m 1s
Run the fuzzers (fuzz_seq_parse_number, true)	4m 5s
	1h 4m 3s

Provide feedback