debug.egl.finish can be used to force a glFinish() when eglSwapBuffers() is called

this debug property is evaludated at eglInitialize() time.

Change-Id: Ie439e4aac87f7fdc6ab2add86183d6d042f3ee8b
diff --git a/opengl/libs/EGL/egl_display.h b/opengl/libs/EGL/egl_display.h
index 6348228..43738ea 100644
--- a/opengl/libs/EGL/egl_display.h
+++ b/opengl/libs/EGL/egl_display.h
@@ -107,6 +107,7 @@
 
 public:
     DisplayImpl     disp;
+    bool    finishOnSwap;
 
 private:
             uint32_t                    refs;