Previous code was using the 'nuclear' SAN weapon `exitcode=0`, which
essentially makes testing ignore all sanitizer errors.
This commit removes this option, and instead uses the suppression
list from Blender source repository (`tools/config/analysis/lsan.supp`)
for the leak sanitizer.
It also enables the `allocator_may_return_null` for the address sanitizer.
This should only be needed for one test (the `guardedalloc` one), but for
now it is simpler to define it for all tests. This can be refined at a
later time.
Pull Request: https://projects.blender.org/blender/blender/pulls/116635
f23ee504d0