Start RenderThread earlier to preload Vulkan/EGL drivers

This CL should fix application startup regression for Vulkan
detected by "Hermetic Startup: EmptyActivity" test.
EGL drivers are loaded in a temp thread to leave more time
in RenderThread for other work. Loading EGL drivers
on the RenderThread may cause a perf regression.

Test: Ran cold-dropcache-test test.
Bug: 122659224
Bug: 123361175
Change-Id: I8ca818e98fac196a41d079be15594caca5cb1bab
diff --git a/libs/hwui/renderthread/RenderProxy.h b/libs/hwui/renderthread/RenderProxy.h
index 6e1bfd7..a1a5551 100644
--- a/libs/hwui/renderthread/RenderProxy.h
+++ b/libs/hwui/renderthread/RenderProxy.h
@@ -131,6 +131,8 @@
 
     ANDROID_API static void disableVsync();
 
+    ANDROID_API static void preload();
+
     static void repackVectorDrawableAtlas();
 
     static void releaseVDAtlasEntries();