Cargo.toml: Disable debug assertions for tests
Recent versions of the toolchain introduced an assert to panic on
unaligned pointer dereferences. We do have some unaligned accesses in
our test suite, and rbpf has been supporting them so far.
As a quick fix, disable debug assertions in the tests. We want to
re-enable them as soon as possible, once we have a solution to avoid
these panics.
Signed-off-by: Quentin Monnet <quentin@isovalent.com>