LibWeb: Don't use the preferred increment as reference for distribution

The specification says we should distribute excess width proportionally
to the width of the cell, not to the preferred increment. Doing the
latter leads to distributing all excess width to just the cells which
demand some increment, even if it's very modest. Moreover, there's code
which partially implements the correct criteria just below the one we
remove here.

Tests/LibWeb/Layout/input/table/width-distribution-of-max-width-increment.html

@@ -0,0 +1,24 @@
+<style>
+    td {
+        border: 1px solid black;
+    }
+
+    table {
+        border-collapse: collapse;
+    }
+</style>
+<table width="100%">
+    <tbody>
+        <tr>
+            <td>
+                A
+            </td>
+            <td>
+                B
+            </td>
+            <td>
+                C D
+            </td>
+        </tr>
+    </tbody>
+</table>