fix the other known opaque types issue

[tjhance]

(depends on #2889)

fixes #2323

In this case, the problem is that the call to opaque_type from the rustc_trait_selection crate depends on mir_borrowck. Replacing this with a call to opaque_type_hir_typeck (which is okay during the hir_typeck phase) solves the issue.

Unfortunately, forking rustc_trait_selection also requires us to fork several crates that depend on it, particularly rustc_hir_typeck and rustc_traits. So this adds a total of 3 crates. (But we wanted to fork rustc_hir_typeck anyway.)

TODO:

• tests
• update the updater script

[tjhance]

Also TODO: see if there are any problems with opaque types from imported crates