Test that if CRCs are computed in task, softirq, and hardirq context
concurrently, then all results are as expected. Implement this using
kunit_run_irq_test() which is also used by the lib/crypto/ tests.
As with the corresponding lib/crypto/ tests, the purpose of this is to
test fallback code paths and to exercise edge cases in the
architecture's support for in-kernel FPU/SIMD/vector.
Remove the code from crc_test() that sometimes disabled interrupts, as
that was just an incomplete attempt to achieve similar test coverage.
Link: https://lore.kernel.org/r/20250811182631.376302-3-ebiggers@kernel.org
Signed-off-by: Eric Biggers <ebiggers@kernel.org>