Update ui test suite to nightly-2026-01-19

Author: dtolnay

tests/ui/enum_assoc.stderr

@@ -3,15 +3,3 @@ error: unsupported self type; C++ does not allow member functions on enums
   |
 7 |         #[Self = "Enum"]
   |                  ^^^^^^
-
-error[E0433]: failed to resolve: use of unresolved module or unlinked crate `ffi`
-  --> tests/ui/enum_assoc.rs:12:6
-   |
-12 | impl ffi::Enum {
-   |      ^^^ use of unresolved module or unlinked crate `ffi`
-   |
-   = help: if you wanted to use a crate named `ffi`, use `cargo add ffi` to add it to your `Cargo.toml`
-help: consider importing this module
-   |
- 1 + use cxx_test_suite::ffi;
-   |