tests: Move run-pass tests without naming conflicts to ui

src/test/ui/mir/mir_codegen_array_2.rs

@@ -0,0 +1,9 @@
+// run-pass
+fn into_inner(x: u64) -> [u64; 1024] {
+    [x; 2*4*8*16]
+}
+
+fn main(){
+    let x: &[u64] = &[42; 1024];
+    assert_eq!(&into_inner(42)[..], x);
+}