Added div element to force horz scroll in table body (#2111)

Fixes #2103
- Added div that is set to the calculated table width. When
filtering is such that no rows are present in the tbody
of the table, this element will still force a horizontal
scroll in that area, allowing the user to horz scroll the headers;

platform/features/table/res/sass/table.scss

@@ -65,3 +65,10 @@ mct-table {
         margin-bottom: 3px;
     }
 }
+
+.mct-table-scroll-forcer {
+    // Force horz scroll when needed; width set via JS
+    font-size: 0;
+    height: 1px; // Height 0 won't force scroll properly
+    position: relative;
+}

platform/features/table/res/templates/mct-table.html

@@ -59,6 +59,10 @@
     </tbody>
 </table>
 <div class="l-tabular-body t-scrolling vscroll--persist" mct-resize="resize()" mct-scroll-x="scroll.x">
+    <div class="mct-table-scroll-forcer"
+         ng-style="{
+        width: totalWidth
+    }"></div>
     <table class="mct-table"
            ng-style="{
             height: totalHeight + 'px',