Fix app bounds for pinned stack

Floating tasks can be positioned partly beyond the parent bounds,
so we shouldn't intersect app bounds rect with its parent for
freeform stack and intersect with offset of pinned stack.

Bug: 37722714
Test: android.server.cts.ActivityManagerPinnedStackTests
Test: #testDisplayMetricsPinUnpin
Change-Id: I0f2c2c1583e9ad85dde24023517c350be0697254
1 file changed