selftests/bpf: Add tests for sdiv/smod overflow cases

Subtests are added to exercise the patched code which handles
  - LLONG_MIN/-1
  - INT_MIN/-1
  - LLONG_MIN%-1
  - INT_MIN%-1
where -1 could be an immediate or in a register.
Without the previous patch, all these cases will crash the kernel on
x86_64 platform.

Additional tests are added to use small values (e.g. -5/-1, 5%-1, etc.)
in order to exercise the additional logic with patched insns.

Signed-off-by: Yonghong Song <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Alexei Starovoitov <[email protected]>

Author: Yonghong Song