Perform stack realignment in every API entry point

Unlikely to cause problems in practice, but technically required since the
compiler is free to use aligned AVX stores to zero local stack-allocated
variables (when using the appropriate compiler flags) for example.
14 jobs for master in 7 minutes and 30 seconds (queued for 24 seconds)
Status Job ID Name Coverage
  Style
passed #245063
amd64 debian
style-check

00:00:21

 
  Build
passed #245064
amd64 debian
build-debian

00:00:33

passed #245069
debian aarch64
build-debian-aarch64

00:01:23

passed #245070
debian aarch64
build-debian-aarch64-clang-5

00:01:03

passed #245065
amd64 debian
build-debian-static

00:00:33

passed #245072
debian aarch64
build-debian-werror

00:00:31

passed #245066
amd64 debian
build-debian32

00:00:26

passed #245071
macos
build-macos

00:00:27

passed #245067
win32
build-win32

00:00:28

passed #245068
win64
build-win64

00:00:35

 
  Test
passed #245073
amd64 debian
test-debian

00:00:46

passed #245074
amd64 debian
test-debian-asan

00:02:03

passed #245075
amd64 debian
test-debian-msan

00:01:01

passed #245076
amd64 debian
test-debian-ubsan

00:01:23