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

src/test/ui/numbers-arithmetic/next-power-of-two-overflow-ndebug.rs

@@ -0,0 +1,14 @@
+// run-pass
+// compile-flags: -C debug_assertions=no
+// ignore-emscripten dies with an LLVM error
+
+fn main() {
+    for i in 129..256 {
+        assert_eq!((i as u8).next_power_of_two(), 0);
+    }
+
+    assert_eq!(((1u16 << 15) + 1).next_power_of_two(), 0);
+    assert_eq!(((1u32 << 31) + 1).next_power_of_two(), 0);
+    assert_eq!(((1u64 << 63) + 1).next_power_of_two(), 0);
+    assert_eq!(((1u128 << 127) + 1).next_power_of_two(), 0);
+}