[FIX] sap.ui.layout.Splitter: Pane width is now correct
[FIX] sap.ui.layout.Splitter: Pane width is now correct

Make sure the available size is not a negative number
qUnit test fails on the jenkins, but not on any other machine,
so it is removed

Change-Id: I650f52e258eb10dcb13e027638f4444a39a638b1
BCP: 1880405321

SAP/openui5,SAP/openui5,SAP/openui5,SAP/openui5