Dynamically adapt SWT on 'SWT.ZoomChanged' event on single monitor.

[niraj-modi]

This bug is to adapt SWT/Eclipse dynamic to changing OS zoom values:
It will require adapting all the SWT widgets to work on the new zoom value.

Note: This is a big ticket item and it will require lot of changes in SWT, here the branch where i could partially achieve this:
https://git.eclipse.org/c/platform/eclipse.platform.swt.git/?h=nmodi%2FDynamicDPI_4909

Since this was partially working then and hence we opted to restart Eclipse on 'SWT.ZoomChanged' event:
https://www.eclipse.org/eclipse/news/4.9/platform.php#zoom-changed