Add LTO test #2395

Job	Run time
build_system	25s
duplicates	3s
build (gcc-13.deb, --mini-tests)	5m 49s
build (gcc-13.deb, --std-tests)	5m 50s
build (gcc-13.deb, --test-libcore)	14m 50s
build (gcc-13.deb, --extended-rand-tests)	8m 21s
build (gcc-13.deb, --extended-regex-example-tests)	6m 29s
build (gcc-13.deb, --extended-regex-tests)	11m 35s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 9s
build (gcc-13.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 5s
build (gcc-13.deb, --projects)	11m 14s
build (gcc-13-without-int128.deb, --mini-tests)	5m 38s
build (gcc-13-without-int128.deb, --std-tests)	5m 43s
build (gcc-13-without-int128.deb, --test-libcore)	14m 24s
build (gcc-13-without-int128.deb, --extended-rand-tests)	8m 8s
build (gcc-13-without-int128.deb, --extended-regex-example-tests)	6m 17s
build (gcc-13-without-int128.deb, --extended-regex-tests)	12m 6s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	11m 30s
build (gcc-13-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	11m 7s
build (gcc-13-without-int128.deb, --projects)	11m 59s
	2h 53m 42s

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