Fix checking of auto trait bounds in trait objects.

Any auto trait is allowed in trait object bounds.
Fix duplicate check of type and lifetime parameter count.

src/test/compile-fail/E0225.rs

@@ -10,6 +10,6 @@
 
 fn main() {
     let _: Box<std::io::Read + std::io::Write>;
-    //~^ ERROR only Send/Sync traits can be used as additional traits in a trait object [E0225]
-    //~| NOTE non-Send/Sync additional trait
+    //~^ ERROR only auto traits can be used as additional traits in a trait object [E0225]
+    //~| NOTE non-auto additional trait
 }

src/test/compile-fail/bad-sized.rs

@@ -12,7 +12,7 @@ trait Trait {}
 
 pub fn main() {
     let x: Vec<Trait + Sized> = Vec::new();
-    //~^ ERROR only Send/Sync traits can be used as additional traits in a trait object
+    //~^ ERROR only auto traits can be used as additional traits in a trait object
     //~| ERROR the trait bound `Trait: std::marker::Sized` is not satisfied
     //~| ERROR the trait bound `Trait: std::marker::Sized` is not satisfied
 }

src/test/compile-fail/issue-22560.rs

@@ -23,6 +23,6 @@ type Test = Add +
             //~| NOTE missing reference to `RHS`
             //~| NOTE because of the default `Self` reference, type parameters must be specified on object types
             //~| ERROR E0225
-            //~| NOTE non-Send/Sync additional trait
+            //~| NOTE non-auto additional trait
 
 fn main() { }

src/test/compile-fail/issue-32963.rs

@@ -16,6 +16,6 @@ fn size_of_copy<T: Copy+?Sized>() -> usize { mem::size_of::<T>() }
 
 fn main() {
     size_of_copy::<Misc+Copy>();
-    //~^ ERROR only Send/Sync traits can be used as additional traits in a trait object
+    //~^ ERROR only auto traits can be used as additional traits in a trait object
     //~| ERROR the trait bound `Misc: std::marker::Copy` is not satisfied
 }

src/test/run-pass/auto-traits.rs

@@ -33,4 +33,7 @@ fn main() {
     take_auto(AutoBool(true));
     take_auto_unsafe(0);
     take_auto_unsafe(AutoBool(true));
+
+    /// Auto traits are allowed in trait object bounds.
+    let _: &(Send + Auto) = &0;
 }