Remove outsets used to crop beyond the task bounds

Having outsets around the task bounds was previously needed to
capture input events outside the task for resizing. With
I70cd2edf5720759e171298c1864854ab81b13b27, it's possible to register
regions beyond the surface for input events, so outsets are no
longer necessary.
This also fixes flickering around the corners/edges during drag
resizing.
Flickering before & after (bottom-right corner):
Before: http://recall/-/fY0xovcFXvWKac90hrLiAe/gxj4XfRMS5BMw6SJJnfOmd
After: http://recall/-/fY0xovcFXvWKac90hrLiAe/hLuUohiTSMNl4mgVkDZqqj

Bug: 270202228
Test: atest WindowDecorationTests
Test: manual: drag resize, verify there's less flickering around the
edge/corner of the task.

Change-Id: Ib9764cf17f23ef9b5688ead7ae93dabbc1155049