tac: remove MMAP use of untrusted source #9748 #5728

Job	Run time
L10n/French Integration Test	1m 55s
L10n/Fluent Syntax Check	15s
L10n/Multi-call Binary Install Test (macos-latest, feat_os_macos)	6m 17s
L10n/Installation Test (Make & Cargo) (ubuntu-latest, feat_os_unix)	7m 34s
L10n/Clap Error Localization Test	1m 38s
L10n/Multi-call Binary Install Test (ubuntu-latest, feat_os_unix)	3m 39s
L10n/Build and Test (macos-latest, feat_os_macos)	54s
L10n/Locale Support Verification	7m 23s
L10n/Build and Test (windows-latest, feat_os_windows)	8m 4s
L10n/Locale Embedding - Cargo Install	1m 14s
L10n/Installation Test (Make & Cargo) (macos-latest, feat_os_macos)	12m 35s
L10n/Locale Embedding - Ls Utility	1m 9s
L10n/Embedded Locale Regression Test	1m 51s
L10n/Build and Test (ubuntu-latest, feat_os_unix)	3m 51s
L10n/Locale Embedding - Multicall Binary	2m 58s
L10n/Locale Embedding - Cat Utility	44s
L10n/Locale Embedding Regression Test	4s
	1h 2m 5s

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