ci: Don't set `compiler-builtins-no-f16-f128` #2908

Job	Run time
duplicates	5s
spell_check	10s
build_system	24s
build (gcc-15.deb, --test-libcore)	1m 38s
build (gcc-15.deb, --extended-rand-tests)	1m 44s
build (gcc-15.deb, --std-tests)	2m 45s
build (gcc-15.deb, --extended-regex-example-tests)	1m 40s
build (gcc-15.deb, --extended-regex-tests)	1m 39s
build (gcc-15-without-int128.deb, --test-libcore)	2m 47s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	6m 4s
build (gcc-15.deb, --projects)	1m 44s
build (gcc-15.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	2m 29s
build (gcc-15-without-int128.deb, --projects)	1m 42s
build (gcc-15-without-int128.deb, --std-tests)	2m 41s
build (gcc-15-without-int128.deb, --extended-regex-tests)	2m 25s
build (gcc-15-without-int128.deb, --extended-rand-tests)	1m 42s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 0)	2m 46s
build (gcc-15-without-int128.deb, --test-successful-rustc --nb-parts 2 --current-part 1)	2m 47s
build (gcc-15-without-int128.deb, --extended-regex-example-tests)	2m 46s
success	4s
	40m 2s

Provide feedback