Auto merge of #62507 - petrochenkov:macunstab, r=alexcrichton

Remove derives `Encodable`/`Decodable` and unstabilize attribute `#[bench]`

`Encodable` and `Decodable` were deprecated before 1.0 and emitted an unsuppressable warning all this time.
`#[bench]` is a part of the custom test framework feature and cannot be used meaningfully on stable, only as `cfg(false)`.

Crater results can be found in https://github.com/rust-lang/rust/pull/62507#issuecomment-513850732 and below.

This PR also reroutes the tracking issue for `feature(test)` from #27812 (compiler internals) to #50297 (custom test frameworks).

Closes https://github.com/rust-lang/rust/issues/62048

src/test/ui/feature-gate/issue-43106-gating-of-builtin-attrs.rs

@@ -32,6 +32,7 @@
 
 // check-pass
 
+#![feature(test)]
 #![warn(unused_attributes, unknown_lints)]
 
 // UNGATED WHITE-LISTED BUILT-IN ATTRIBUTES

src/test/ui/issues/issue-12997-1.rs

@@ -2,6 +2,8 @@
 
 //! Test that makes sure wrongly-typed bench functions aren't ignored
 
+#![feature(test)]
+
 #[bench]
 fn foo() { } //~ ERROR functions used as benches
 

src/test/ui/issues/issue-12997-1.stderr

@@ -1,11 +1,11 @@
 error: functions used as benches must have signature `fn(&mut Bencher) -> impl Termination`
-  --> $DIR/issue-12997-1.rs:6:1
+  --> $DIR/issue-12997-1.rs:8:1
    |
 LL | fn foo() { }
    | ^^^^^^^^^^^^
 
 error: functions used as benches must have signature `fn(&mut Bencher) -> impl Termination`
-  --> $DIR/issue-12997-1.rs:9:1
+  --> $DIR/issue-12997-1.rs:11:1
    |
 LL | fn bar(x: isize, y: isize) { }
    | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/test/ui/issues/issue-12997-2.rs

@@ -2,6 +2,8 @@
 
 //! Test that makes sure wrongly-typed bench functions are rejected
 
+#![feature(test)]
+
 #[bench]
 fn bar(x: isize) { }
 //~^ ERROR mismatched types

src/test/ui/issues/issue-12997-2.stderr

@@ -1,5 +1,5 @@
 error[E0308]: mismatched types
-  --> $DIR/issue-12997-2.rs:6:1
+  --> $DIR/issue-12997-2.rs:8:1
    |
 LL | fn bar(x: isize) { }
    | ^^^^^^^^^^^^^^^^^^^^ expected isize, found mutable reference

src/test/ui/json-multiple.rs

@@ -1,4 +1,5 @@
 // build-pass
+// ignore-pass (different metadata emitted in different modes)
 // compile-flags: --json=diagnostic-short --json artifacts --error-format=json
 
 #![crate_type = "lib"]

src/test/ui/json-options.rs

@@ -1,4 +1,5 @@
 // build-pass
+// ignore-pass (different metadata emitted in different modes)
 // compile-flags: --json=diagnostic-short,artifacts --error-format=json
 
 #![crate_type = "lib"]