Fix tests failing on qemu

[mkannwischer]

#4 identified that 5 tests are currently non-functional on the qemu m55-an547 platform:

• chunk
• montgomery
• ntt-1024
• saber
• schoolbook

They are currently commented out in the root Makefile and won't run in CI.

I don't have any bandwidth to debug those, and I have little interest to keep maintaining them.
They are all unrelated to SLOTHY and come from https://gitlab.com/arm-research/security/pqmx.
If someone wants to fix them, please go ahead. If not fixed by the end of the year, it's probably better to delete them here to not pollute the repo too much.

[hanno-becker]

chunk fixed in #9

[hanno-becker]

montgomery fixed in #9

[hanno-becker]

Fixed Saber test in #11

[hanno-becker]

Removed schoolbook test in #11

[hanno-becker]

ntt-1024 fixed in #12