expr: fix regex matching on inputs containing newlines #18153

Job	Run time
Build and test uufuzz examples	1m 14s
Build the fuzzers	1m 15s
Fuzz (fuzz_printf, true)	2m 14s
Fuzz (fuzz_expr, true)	3m 43s
Fuzz (fuzz_non_utf8_paths, true)	2m 24s
Fuzz (fuzz_parse_size, false)	1m 12s
Fuzz (fuzz_date, true)	2m 11s
Fuzz (fuzz_echo, true)	2m 33s
Fuzz (fuzz_seq, false)	1m 6s
Fuzz (fuzz_parse_glob, true)	2m 15s
Fuzz (fuzz_cut, false)	1m 8s
Fuzz (fuzz_wc, false)	1m 13s
Fuzz (fuzz_split, false)	1m 14s
Fuzz (fuzz_cksum, false)	1s
Fuzz (fuzz_dirname, true)	2m 28s
Fuzz (fuzz_env, false)	1s
Fuzz (fuzz_test, true)	25s
Fuzz (fuzz_parse_time, false)	1s
Fuzz (fuzz_sort, false)	54s
Fuzz (fuzz_seq_parse_number, false)	1s
Fuzz (fuzz_tr, false)	1m 46s
Fuzzing Summary	8s
Build and test uufuzz examples	1m 14s
Fuzz (fuzz_sort, false)	54s
Fuzz (fuzz_expr, true)	3m 43s
Fuzz (fuzz_cut, false)	1m 8s
Fuzz (fuzz_printf, true)	2m 14s
Fuzz (fuzz_wc, false)	1m 13s
Fuzz (fuzz_test, true)	25s
Fuzz (fuzz_tr, false)	1m 46s
Fuzz (fuzz_date, true)	3m 49s
Fuzz (fuzz_seq, false)	1m 6s
Fuzz (fuzz_split, false)	1m 14s
Fuzz (fuzz_seq_parse_number, false)	1s
Fuzz (fuzz_parse_time, false)	1s
Fuzz (fuzz_parse_glob, true)	2m 15s
Fuzz (fuzz_env, false)	1s
Fuzz (fuzz_cksum, false)	1s
Fuzz (fuzz_parse_size, false)	1m 12s
Fuzz (fuzz_non_utf8_paths, true)	2m 24s
Fuzz (fuzz_dirname, true)	2m 28s
Build the fuzzers	1m 15s
Fuzz (fuzz_echo, true)	2m 33s
Fuzzing Summary	10s
	1h 0m 34s

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