Normal Miri does not provide sufficient safety guarantees. Using the flag `-Zmiri-tag-raw-pointers` also checks usage of pointers in a more strict way.
* Ensure functions that take generic <A, B> don't call them <T, U>
* Plug soundness hole in offset_of with safe_packed_borrows lint
* Add some more tests I noticed were missing (still many missing)
* Make CI way more thorough
* Fix running MSRV tests with unsupported `--feature`s
* Disable derive tests in sanitizers, and fix miri ci