Auto merge of #13637 - jhpratt:master, r=weihanglo

Remove unnecessary test

This removes a test that is blocking rust-lang/rust#116016 from landing. `@dtolnay` suggested removing the test rather than allowing the relevant lints ([comment](rust-lang/rust#116016 (comment))).

> The failure is in https://github.com/rust-lang/cargo/blob/77506e57392d94450bb3ed52cf75e3263bbb2792/tests/testsuite/check.rs#L222-L285 which is a 7 year old test for [#3419](#3419), which is from 2 days after the initial implementation of `cargo check` landed in nightly Cargo in [#3296](#3296).
>
> I would recommend just deleting the test from Cargo. The implementation of `cargo check` has matured enough since then and I don't see anything useful in that test.

tests/testsuite/check.rs

@@ -219,71 +219,6 @@ fn issue_3418() {
         .run();
 }
 
-// Some weirdness that seems to be caused by a crate being built as well as
-// checked, but in this case with a proc macro too.
-#[cargo_test]
-fn issue_3419() {
-    let p = project()
-        .file(
-            "Cargo.toml",
-            r#"
-                [package]
-                name = "foo"
-                version = "0.0.1"
-                edition = "2015"
-                authors = []
-
-                [dependencies]
-                rustc-serialize = "*"
-            "#,
-        )
-        .file(
-            "src/lib.rs",
-            r#"
-                extern crate rustc_serialize;
-
-                use rustc_serialize::Decodable;
-
-                pub fn take<T: Decodable>() {}
-            "#,
-        )
-        .file(
-            "src/main.rs",
-            r#"
-                extern crate rustc_serialize;
-
-                extern crate foo;
-
-                #[derive(RustcDecodable)]
-                pub struct Foo;
-
-                fn main() {
-                    foo::take::<Foo>();
-                }
-            "#,
-        )
-        .build();
-
-    Package::new("rustc-serialize", "1.0.0")
-        .file(
-            "src/lib.rs",
-            r#"
-                pub trait Decodable: Sized {
-                    fn decode<D: Decoder>(d: &mut D) -> Result<Self, D::Error>;
-                }
-                pub trait Decoder {
-                   type Error;
-                   fn read_struct<T, F>(&mut self, s_name: &str, len: usize, f: F)
-                                        -> Result<T, Self::Error>
-                   where F: FnOnce(&mut Self) -> Result<T, Self::Error>;
-                }
-            "#,
-        )
-        .publish();
-
-    p.cargo("check").run();
-}
-
 // Check on a dylib should have a different metadata hash than build.
 #[cargo_test]
 fn dylib_check_preserves_build_cache() {