CI: Setup jobs with ASan

[solardiz]

We need to add CI jobs that would use ASan. For this, we could want to implement #40 first.

[solardiz]

For now, I manually tested with:

make CFLAGS='-Wall -W -O2 -fsanitize=address,undefined,pointer-compare,pointer-subtract,leak' LDFLAGS='-fsanitize=address,undefined'