Clean up featuresutils library

dlclose the featureutils library when closing the driver.
Had tried closing inside load_angle but that won't work
due to threading and we will have a featureutil resource
we want to keep around.

Bug: 118613436
Bug: 118375731
Test: monkey UI testing
Test: cts-tradefed run singleCommand cts -m CtsAngleIntegrationHostTestCases

Change-Id: I40b13c679665951935f0e7254f24c384645365f3
diff --git a/opengl/libs/EGL/egldefs.h b/opengl/libs/EGL/egldefs.h
index e19fa38..cca0053 100644
--- a/opengl/libs/EGL/egldefs.h
+++ b/opengl/libs/EGL/egldefs.h
@@ -80,6 +80,7 @@
     bool                useAngle;
     EGLint              angleBackend;
     void*               vendorEGL;
+    void*               featureSo;
 };
 // clang-format on