Fix the tests of the crate portable-atomic #821
Description
There are some failures on x86-64:
- test imp::atomic128::x86_64::tests::test_atomic_u128::compare_exchange ... FAILED
- test imp::atomic128::x86_64::tests::test_atomic_u128::compare_exchange_weak ... FAILED
- test imp::atomic128::x86_64::tests::test_atomic_u128::load_store ... SIGSEGV
and even more failures on m68k.
- Run the test of this crate in the CI?