This allows loading layers for GLES and Vulkan at the
same time by adding a GLES specific setting:
GPU_DEBUG_LAYERS_GLES
which mirrors the existing setting:
GPU_DEBUG_LAYERS
The Vulkan and GLES loaders now scan distinct layer
lists, correcting an issue that would prevent Vulkan
from loading when it failed to find GLES layers.
Bug: 110883880
Test: Load a GLES layer when running ANGLE with Vulkan backend
Test: cts-tradefed run singleCommand cts -m CtsGpuToolsHostTestCases
Change-Id: I370be4ce6fdde9e95989eb1f274add8b5790263e
0fa1d220dc