Add UBENCH_ATTRIBUTE #19

Job	Run time
build (ubuntu-latest, Debug, address)	38s
build (ubuntu-latest, Debug, memory)	32s
build (ubuntu-latest, Debug, undefined)	19s
build (ubuntu-latest, RelWithDebInfo, address)	25s
build (ubuntu-latest, RelWithDebInfo, memory)	43s
build (ubuntu-latest, RelWithDebInfo, undefined)	20s
build (ubuntu-latest, MinSizeRel, address)	34s
build (ubuntu-latest, MinSizeRel, memory)	26s
build (ubuntu-latest, MinSizeRel, undefined)	48s
build (ubuntu-latest, Release, address)	24s
build (ubuntu-latest, Release, memory)	25s
build (ubuntu-latest, Release, undefined)	19s
build (macOS-latest, Debug, address)	36s
build (macOS-latest, Debug, undefined)	29s
build (macOS-latest, RelWithDebInfo, address)	1m 37s
build (macOS-latest, RelWithDebInfo, undefined)	28s
build (macOS-latest, MinSizeRel, address)	37s
build (macOS-latest, MinSizeRel, undefined)	26s
build (macOS-latest, Release, address)	37s
build (macOS-latest, Release, undefined)	30s
	11m 13s

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