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

src/test/ui/for-loop-while/while-loop-constraints-2.rs

@@ -0,0 +1,15 @@
+// run-pass
+#![allow(unused_assignments)]
+#![allow(unused_variables)]
+
+pub fn main() {
+    let mut y: isize = 42;
+    let mut z: isize = 42;
+    let mut x: isize;
+    while z < 50 {
+        z += 1;
+        while false { x = y; y = z; }
+        println!("{}", y);
+    }
+    assert!((y == 42 && z == 50));
+}