[harmony-demo-1] 8 tests fixed in Metal Root Pane tests

[Mackie Mathew]

https://issues.apache.org/jira/browse/HARMONY-5894

I've been able to fix 8 tests in MetalRootPaneUI$MetalRootLayoutTest,
MetalRootPaneUIRTest and MetalRootPaneUITest.

Regards,

Tharindu