* Late Lint pass, catches:
* One liner: 0 -> null -> transmute
* One liner: std:null() -> transmute
* Const (which resolves to null) -> transmute
* UI Test case for Lint
* Updated test for issue 3849, because now the lint that code generated is in Clippy.
* Expanded `const.rs` miri-based Constant Folding code, to cover
raw pointers
