Remove Sky tests that we don't intend to port to the new world

sky/tests/lowlevel/layers-expected.sky

Index: sky/tests/lowlevel/layers-expected.sky
diff --git a/sky/tests/lowlevel/layers-expected.sky b/sky/tests/lowlevel/layers-expected.sky
deleted file mode 100644
index b923a4cec33eb93cd93633d1a7b024d41e555b5d..0000000000000000000000000000000000000000
--- a/sky/tests/lowlevel/layers-expected.sky
+++ /dev/null
@@ -1,18 +0,0 @@
-<foo>
-<import src="../resources/run-after-display.sky" />
-
-<img src="http://storage.googleapis.com/mojo/sky-pngs/8ce0b808d5248b9e7ed051046def933f6ffaa889" />
-
-<script>
-import "dart:sky";
-import "dart:sky.internals" as internals;
-
-void main() {
-  window.addEventListener('load', (_) {
-    runAfterDisplay(() {
-      internals.notifyTestComplete("");
-    });
-  });
-}
-</script>
-</foo>