Layer: Guard against Region offset overflows

When applying a transform to a Region, if the Region is translated to
bounds that overlow the int32_t type, the process crashes.

For now, we guard against process crashes by manually applying the
offset to the Region and checking for overflows. If we detect an
overflow in one of the Rects in a Region, we remove the Rect from the
resulting Region.

Bug: 234247210
Test: atest libgui_test
Change-Id: Icd47539accae2e59a7dbd9c9621201bd040fc402