Rollup merge of #77439 - varkor:min_const_generics-tests, r=lcnr,estebank

Fix missing diagnostic span for `impl Trait` with const generics, and add various tests for `min_const_generics` and `const_generics`

Closes https://github.com/rust-lang/rust/issues/61410.

Adds `min_const_generics` tests for:
- https://github.com/rust-lang/rust/issues/73727
- https://github.com/rust-lang/rust/issues/72293
- https://github.com/rust-lang/rust/issues/67375
- https://github.com/rust-lang/rust/issues/75153
- https://github.com/rust-lang/rust/issues/71922
- https://github.com/rust-lang/rust/issues/69913
- https://github.com/rust-lang/rust/issues/67945
- https://github.com/rust-lang/rust/issues/69239

Adds `const_generics` tests for:
- https://github.com/rust-lang/rust/issues/67375
- https://github.com/rust-lang/rust/issues/75153
- https://github.com/rust-lang/rust/issues/71922
- https://github.com/rust-lang/rust/issues/69913
- https://github.com/rust-lang/rust/issues/67945
- https://github.com/rust-lang/rust/issues/69239

(I only added separate `min_const_generics` and `const_generics` tests if they were handled differently by the two features.)

We need to figure out how to deduplicate when `const_generics` is stabilised, but we can discuss that later. For now, we should be checking neither feature breaks, so require regression tests for both. I've given them identical names when I've added both, which should make it easier to spot them later.

r? @lcnr

compiler/rustc_feature/src/active.rs

@@ -581,7 +581,7 @@ declare_features! (
     /// Allows `if let` guard in match arms.
     (active, if_let_guard, "1.47.0", Some(51114), None),
 
-    /// Allows non trivial generic constants which have to be manually propageted upwards.
+    /// Allows non-trivial generic constants which have to be manually propageted upwards.
     (active, const_evaluatable_checked, "1.48.0", Some(76560), None),
 
     /// Allows basic arithmetic on floating point types in a `const fn`.