Fix RenderNodeDrawable to draw nonzero Z nodes when needed

Fix RenderNodeDrawable to draw nonzero Z nodes if not in a reordering
section.
Write an unit test modeled after FrameBuilder zReorder, which
verifies the bug fix.

Test: built and run unit tests on angler-eng.
bug: 32541103
Change-Id: Ifbf2d51f4432f5de3af4abe5987c2a72fed14185
4 files changed