Consolidate filling of window frames and config for client

The data for client window are only used in WMS#relayoutWindow
and WS#reportResized, so the operations can be done in a single
method fillClientWindowFramesAndConfiguration.

This also eliminates redundant operation when calling
setLastReportedMergedConfiguration with the value returned by
getLastReportedMergedConfiguration.

Bug: 159103089
Test: CtsWindowManagerDeviceTestCases
Change-Id: Idb93b3a80d3dd0c60e3d9567ca79c10060fca55c