Support insets on secondary displays

Indroduced DisplayFrames object to track frames used to calculate
window insets per display vs. at a global level in PhoneWindowManager.

Bug: 64148922
Change-Id: I19f166920eba0a4f933a223a77e096bcc8dab0c1
Test: bit FrameworksServicesTests:com.android.server.wm.ScreenDecorWindowTests
Test: go/wm-smoke