Remove impl_trait_in_bindings handling on inference error reporting

src/test/ui/inference/cannot-infer-async-enabled-impl-trait-bindings.rs

@@ -1,17 +0,0 @@
-// edition:2018
-#![feature(impl_trait_in_bindings)]
-//~^ WARN the feature `impl_trait_in_bindings` is incomplete
-
-use std::io::Error;
-
-fn make_unit() -> Result<(), Error> {
-    Ok(())
-}
-
-fn main() {
-    let fut = async {
-        make_unit()?;
-
-        Ok(()) //~ ERROR type annotations needed
-    };
-}

src/test/ui/inference/cannot-infer-async-enabled-impl-trait-bindings.stderr

@@ -1,21 +0,0 @@
-warning: the feature `impl_trait_in_bindings` is incomplete and may not be safe to use and/or cause compiler crashes
-  --> $DIR/cannot-infer-async-enabled-impl-trait-bindings.rs:2:12
-   |
-LL | #![feature(impl_trait_in_bindings)]
-   |            ^^^^^^^^^^^^^^^^^^^^^^
-   |
-   = note: `#[warn(incomplete_features)]` on by default
-   = note: see issue #63065 <https://github.com/rust-lang/rust/issues/63065> for more information
-
-error[E0282]: type annotations needed for `impl Future`
-  --> $DIR/cannot-infer-async-enabled-impl-trait-bindings.rs:15:9
-   |
-LL |     let fut = async {
-   |         --- consider giving `fut` the explicit type `impl Future`, where the type parameter `E` is specified
-...
-LL |         Ok(())
-   |         ^^ cannot infer type for type parameter `E` declared on the enum `Result`
-
-error: aborting due to previous error; 1 warning emitted
-
-For more information about this error, try `rustc --explain E0282`.