Use RGBA16F layers when wide color gamut rendering is on

Layers created using View.setLayerType() or Canvas.saveLayer() need
to be RGBA16F/scRGB-nl when within a window that requested wide color
gamut rendering.

Bug: 29940137
Test: CtsUiRenderingTestCases, CtsGraphicsTestCases, hwui_unit_tests
Change-Id: I42fd6355448c92041491a7109e3ac8a153d38bf9