ci: Don't set `compiler-builtins-no-f16-f128` #2910

Job	Run time
duplicates	5s
build_system	26s
spell_check	8s
build (gcc-15.deb, --std-tests)	1m 51s
build (gcc-15.deb, --extended-rand-tests)	1m 46s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	2m 4s
build (gcc-15-without-int128.deb, --std-tests)	5m 19s
build (gcc-15-without-int128.deb, --extended-regex-tests)	2m 13s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	2m 4s
build (gcc-15-without-int128.deb, --extended-regex-example-tests)	1m 0s
build (gcc-15.deb, --extended-regex-tests)	1m 7s
build (gcc-15-without-int128.deb, --extended-rand-tests)	1m 2s
build (gcc-15.deb, --test-libcore)	1m 9s
build (gcc-15-without-int128.deb, --projects)	1m 10s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	1m 14s
build (gcc-15.deb, --extended-regex-example-tests)	2m 18s
build (gcc-15-without-int128.deb, --test-libcore)	2m 25s
build (gcc-15.deb, --projects)	1m 2s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	1m 57s
success	5s
	30m 25s

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