pipes.rs: add missing count on fallback #24342

Job	Run time
Build and test uufuzz examples	1m 6s
Build the fuzzers	2m 44s
Fuzz (fuzz_printf, true)	3m 15s
Fuzz (fuzz_seq, false)	2m 16s
Fuzz (fuzz_wc, false)	2m 24s
Fuzz (fuzz_test, true)	3m 26s
Fuzz (fuzz_cut, false)	2m 17s
Fuzz (fuzz_date, true)	3m 19s
Fuzz (fuzz_split, false)	2m 39s
Fuzz (fuzz_sort, false)	2m 50s
Fuzz (fuzz_expr, true)	3m 16s
Fuzz (fuzz_tr, false)	2m 29s
Fuzz (fuzz_env, false)	2m 27s
Fuzz (fuzz_dirname, true)	3m 20s
Fuzz (fuzz_parse_size, false)	2m 24s
Fuzz (fuzz_cksum, false)	3m 10s
Fuzz (fuzz_non_utf8_paths, true)	3m 13s
Fuzz (fuzz_parse_glob, true)	3m 9s
Fuzz (fuzz_echo, true)	3m 17s
Fuzz (fuzz_parse_time, false)	2m 23s
Fuzz (fuzz_seq_parse_number, false)	1m 55s
Fuzzing Summary	8s
	57m 27s

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