LibWeb: Use clip rectangles assigned to paintables in hit-testing

This change makes hit-testing more consistent in the handling of hidden
overflow by reusing the same clip-rectangles.

Also, it fixes bugs where the box is visible for hit-testing even
though it is clipped by the hidden overflow of the containing block.

Tests/LibWeb/Text/input/hit_testing/click-outside-of-box-with-hidden-overflow.html

@@ -0,0 +1,23 @@
+<script src="../include.js"></script>
+<style>
+    .overflow-hidden {
+        overflow: hidden;
+        border: 1px solid black;
+        width: 200px;
+        height: 200px;
+    }
+
+    #box {
+        width: 400px;
+        height: 400px;
+        background-color: red;
+    }
+</style>
+<div class="overflow-hidden">
+    <div id="box"></div>
+</div>
+<script type="text/javascript">
+    test(() => {
+        printElement(internals.hitTest(300, 300).node);
+    });
+</script>