std_detect: add avx512fp16 #1931

Job	Run time
Check Style	14s
Automatic intrinsic verification	27s
Test (i686-unknown-linux-gnu)	1m 37s
Build Documentation	1m 8s
Build std_detect	1m 4s
Test (x86_64-unknown-linux-gnu)	1m 36s
Env Override	15s
Test (x86_64-unknown-linux-gnu-emulated)	1m 35s
Test (arm-unknown-linux-gnueabihf)	1m 16s
Test (armv7-unknown-linux-gnueabihf)	1m 37s
Test (aarch64-unknown-linux-gnu)	1m 22s
Test (riscv64gc-unknown-linux-gnu)	1m 17s
Test (powerpc64le-unknown-linux-gnu)	1m 35s
Test (s390x-unknown-linux-gnu)	1m 28s
Test (wasm32-wasi)	1m 29s
Test (i586-unknown-linux-gnu)	1m 38s
Test (nvptx64-nvidia-cuda)	34s
Test (thumbv6m-none-eabi)	13s
Test (thumbv7m-none-eabi)	13s
Test (thumbv7em-none-eabi)	15s
Test (thumbv7em-none-eabihf)	13s
Test (aarch64-apple-darwin)	1m 33s
Test (x86_64-pc-windows-msvc)	1m 32s
Test (i686-pc-windows-msvc)	1m 31s
Test (x86_64-apple-darwin, macos-11)	1m 32s
success	1s
	27m 15s

Provide feedback