Fix #14941: FN memleak with `_create_locale` #20508

Job	Run time
build_cmake (ubuntu:25.10, true, true)	6m 5s
build_make (ubuntu:24.04)	4m 36s
build_cmake (alpine:3.23, false, false)	2m 59s
build_cmake (ubuntu:24.04, true, true)	2m 56s
build_make (ubuntu:25.10)	3m 25s
build_make (alpine:3.23)	5m 56s
	25m 57s

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