Add GLES specific setting for layers

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
diff --git a/services/core/java/com/android/server/am/CoreSettingsObserver.java b/services/core/java/com/android/server/am/CoreSettingsObserver.java
index 48e26ed..968c17f 100644
--- a/services/core/java/com/android/server/am/CoreSettingsObserver.java
+++ b/services/core/java/com/android/server/am/CoreSettingsObserver.java
@@ -59,6 +59,7 @@
         sGlobalSettingToTypeMap.put(Settings.Global.ENABLE_GPU_DEBUG_LAYERS, int.class);
         sGlobalSettingToTypeMap.put(Settings.Global.GPU_DEBUG_APP, String.class);
         sGlobalSettingToTypeMap.put(Settings.Global.GPU_DEBUG_LAYERS, String.class);
+        sGlobalSettingToTypeMap.put(Settings.Global.GPU_DEBUG_LAYERS_GLES, String.class);
         sGlobalSettingToTypeMap.put(Settings.Global.GPU_DEBUG_LAYER_APP, String.class);
         // add other global settings here...
     }