libcore tests: avoid int2ptr casts We don't need any of these pointers to actually be dereferenceable so using `ptr::invalid` should be fine. And then we can run Miri with strict provenance enforcement on the tests.
libcore tests: avoid int2ptr casts We don't need any of these pointers to actually be dereferenceable so using `ptr::invalid` should be fine. And then we can run Miri with strict provenance enforcement on the tests.