Move some tests to more reasonable directories

src/test/ui/issues/issue-5791.rs

@@ -1,14 +0,0 @@
-// run-pass
-#![allow(dead_code)]
-#![warn(clashing_extern_declarations)]
-// pretty-expanded FIXME #23616
-
-extern "C" {
-    #[link_name = "malloc"]
-    fn malloc1(len: i32) -> *const u8;
-    #[link_name = "malloc"]
-    //~^ WARN `malloc2` redeclares `malloc` with a different signature
-    fn malloc2(len: i32, foo: i32) -> *const u8;
-}
-
-pub fn main() {}

src/test/ui/issues/issue-5791.stderr

@@ -1,21 +0,0 @@
-warning: `malloc2` redeclares `malloc` with a different signature
-  --> $DIR/issue-5791.rs:9:5
-   |
-LL | /     #[link_name = "malloc"]
-LL | |     fn malloc1(len: i32) -> *const u8;
-   | |______________________________________- `malloc` previously declared here
-LL | /     #[link_name = "malloc"]
-LL | |
-LL | |     fn malloc2(len: i32, foo: i32) -> *const u8;
-   | |________________________________________________^ this signature doesn't match the previous declaration
-   |
-note: the lint level is defined here
-  --> $DIR/issue-5791.rs:3:9
-   |
-LL | #![warn(clashing_extern_declarations)]
-   |         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-   = note: expected `unsafe extern "C" fn(i32) -> *const u8`
-              found `unsafe extern "C" fn(i32, i32) -> *const u8`
-
-warning: 1 warning emitted
-