Bug#1076436: highway: Add autopkgtest.

[Jeremy Bícha]

Could you use either a git formatted patch or a Salsa merge request
for further iterations of this submission? I believe
debian/tests/compile-and-execute should be marked as executable since
it's a shell script but that information is not encoded in your diff
file.

I believe it is more convenient for most Debian maintainers if you
don't edit debian/changelog directly but write an appropriate commit
message that can be used by gbp dch.

When I tried building this with sbuild for Debian Unstable today, I
got this error:

autopkgtest [12:04:48]: test compile-and-execute: [-----------------------
+ trap rm o 0
+ pkg-config --cflags --libs libhwy
+ cflags=-DHWY_SHARED_DEFINE -lhwy
+ c++ -x c++ - -o o -fsanitize=address -Wall -Wextra -Wpedantic
-DHWY_SHARED_DEFINE -lhwy
+ ./o
==83347==ASan runtime does not come first in initial library list; you
should either link runtime to your application or manually preload it
with LD_PRELOAD.
+ rm o

Thank you,
Jeremy Bícha