Add CI compiling rustc #3139

Job	Run time
spell_check	8s
duplicates	5s
build_system	44s
build (gcc-15.deb, --std-tests)	5m 50s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	13m 54s
build (gcc-15.deb, --test-libcore)	16m 40s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	14m 7s
build (gcc-15.deb, --extended-regex-example-tests)	6m 34s
build (gcc-15.deb, --extended-regex-tests)	11m 18s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	14m 15s
build (gcc-15-without-int128.deb, --std-tests)	6m 9s
build (gcc-15-without-int128.deb, --extended-regex-tests)	11m 46s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	14m 17s
build (gcc-15.deb, --projects)	11m 52s
build (gcc-15.deb, --extended-rand-tests)	9m 5s
build (gcc-15-without-int128.deb, --test-libcore)	17m 2s
build (gcc-15-without-int128.deb, --extended-rand-tests)	8m 47s
build (gcc-15-without-int128.deb, --projects)	11m 14s
build (gcc-15-without-int128.deb, --extended-regex-example-tests)	6m 43s
success	3s
	3h 0m 33s

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