QmlDesigner: Remove unused "split editor" icon pngs

The handling of form editor and code editor are now done via the docking
system, the png are unused.

Amends: 1a8c802f56

Change-Id: Iecddc4f68f605abcaad1b9072a128a247f344349
Reviewed-by: Mahmoud Badri <mahmoud.badri@qt.io>

src/plugins/qmldesigner/components/resources/resources.qrc

@@ -5,9 +5,5 @@
         <file>formeditorstylesheet.css</file>
         <file>centerwidget.css</file>
         <file>dockwidgets.css</file>
-        <file>images/spliteditorhorizontally.png</file>
-        <file>images/spliteditorhorizontally@2x.png</file>
-        <file>images/spliteditorvertically.png</file>
-        <file>images/spliteditorvertically@2x.png</file>
     </qresource>
 </RCC>

src/tools/icons/qtcreatoricons.svg

@@ -10361,42 +10361,6 @@
          d="M 636.00003,403 H 641 v -4.67861 l -4.99997,0.67433 z M 642,398.18129 V 403 h 6.00003 v -5.6287 z m 0,10.72061 6.00003,0.81345 V 404 H 642 Z M 636.00003,408.09093 641,408.7667 V 404 h -4.99997 z"
          id="path5333" />
     </g>
-    <g
-       id="src/plugins/qmldesigner/components/resources/images/spliteditorvertically"
-       transform="translate(12)">
-      <rect
-         transform="rotate(90)"
-         id="rect5154-0-3-5-8-1-6-8"
-         height="8"
-         width="16"
-         y="-858"
-         x="584"
-         style="fill:#ffffff" />
-      <path
-         id="formEditorSplit_"
-         style="fill:none;stroke:#000000"
-         d="m 852,592.5 h 5 m -5.5,-3 h 6 v 6 h -6 z"
-         inkscape:connector-curvature="0" />
-    </g>
-    <g
-       id="src/plugins/qmldesigner/components/resources/images/spliteditorhorizontally">
-      <rect
-         style="fill:#ffffff"
-         x="584"
-         y="-878"
-         width="16"
-         height="8"
-         id="rect5704"
-         transform="rotate(90)" />
-      <use
-         height="100%"
-         width="100%"
-         transform="rotate(90,864.5,602.5)"
-         id="use5730"
-         xlink:href="#formEditorSplit_"
-         y="0"
-         x="0" />
-    </g>
     <g
        id="src/plugins/debugger/images/debugger_stop_mask"
        transform="translate(-711,333)"