Flatten effects directory now that it doesn't really test anything specific

tests/ui/traits/const-traits/effects/auxiliary/cross-crate.rs

@@ -1,13 +0,0 @@
-//@ compile-flags: -Znext-solver
-#![feature(const_trait_impl)]
-
-pub const fn foo() {}
-
-#[const_trait]
-pub trait Bar {
-    fn bar();
-}
-
-impl Bar for () {
-    fn bar() {}
-}

tests/ui/traits/const-traits/effects/no-explicit-const-params-cross-crate.rs

@@ -1,18 +0,0 @@
-//@ aux-build: cross-crate.rs
-extern crate cross_crate;
-
-use cross_crate::{Bar, foo};
-
-fn main() {
-    foo::<true>();
-    //~^ ERROR: function takes 0 generic arguments but 1 generic argument was supplied
-    <() as Bar<true>>::bar();
-    //~^ ERROR: trait takes 0 generic arguments but 1 generic argument was supplied
-}
-
-const FOO: () = {
-    foo::<false>();
-    //~^ ERROR: function takes 0 generic arguments but 1 generic argument was supplied
-    <() as Bar<false>>::bar();
-    //~^ ERROR: trait takes 0 generic arguments but 1 generic argument was supplied
-};

tests/ui/traits/const-traits/effects/no-explicit-const-params-cross-crate.stderr

@@ -1,59 +0,0 @@
-error[E0107]: function takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/no-explicit-const-params-cross-crate.rs:14:5
-   |
-LL |     foo::<false>();
-   |     ^^^--------- help: remove the unnecessary generics
-   |     |
-   |     expected 0 generic arguments
-   |
-note: function defined here, with 0 generic parameters
-  --> $DIR/auxiliary/cross-crate.rs:4:14
-   |
-LL | pub const fn foo() {}
-   |              ^^^
-
-error[E0107]: trait takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/no-explicit-const-params-cross-crate.rs:16:12
-   |
-LL |     <() as Bar<false>>::bar();
-   |            ^^^------- help: remove the unnecessary generics
-   |            |
-   |            expected 0 generic arguments
-   |
-note: trait defined here, with 0 generic parameters
-  --> $DIR/auxiliary/cross-crate.rs:7:11
-   |
-LL | pub trait Bar {
-   |           ^^^
-
-error[E0107]: function takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/no-explicit-const-params-cross-crate.rs:7:5
-   |
-LL |     foo::<true>();
-   |     ^^^-------- help: remove the unnecessary generics
-   |     |
-   |     expected 0 generic arguments
-   |
-note: function defined here, with 0 generic parameters
-  --> $DIR/auxiliary/cross-crate.rs:4:14
-   |
-LL | pub const fn foo() {}
-   |              ^^^
-
-error[E0107]: trait takes 0 generic arguments but 1 generic argument was supplied
-  --> $DIR/no-explicit-const-params-cross-crate.rs:9:12
-   |
-LL |     <() as Bar<true>>::bar();
-   |            ^^^------ help: remove the unnecessary generics
-   |            |
-   |            expected 0 generic arguments
-   |
-note: trait defined here, with 0 generic parameters
-  --> $DIR/auxiliary/cross-crate.rs:7:11
-   |
-LL | pub trait Bar {
-   |           ^^^
-
-error: aborting due to 4 previous errors
-
-For more information about this error, try `rustc --explain E0107`.