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

sky/tests/layout/margins.sky

Index: sky/tests/layout/margins.sky
diff --git a/sky/tests/layout/margins.sky b/sky/tests/layout/margins.sky
deleted file mode 100644
index f720072e738f6d2c090794fefdb6c4be2bcd9f29..0000000000000000000000000000000000000000
--- a/sky/tests/layout/margins.sky
+++ /dev/null
@@ -1,23 +0,0 @@
-<sky>
-  <import src="../resources/check-layout.sky" as="checkLayout" />
-  <style>
-  .root {
-    margin: 5px;
-  }
-  .child {
-    margin: 10px;
-    height: 30px;
-  }
-  </style>
-  <div class="root" data-expected-height="100" data-total-y="5" style="background-color: pink">
-    <!-- TODO(ojan): These numbers are right, but the test fails because we appear to have
-    broken offsetTop to not include the parent's margin-top. -->
-    <div class="child" data-total-y="15" style="background-color: salmon"></div>
-    <div class="child" data-total-y="65" style="background-color: papayawhip"></div>
-  </div>
-
-  <script>
-    checkLayout('.root');
-  </script>
-</sky>
-