Fix EGL tests that called EGL functions before init()

Fix EGL tests that called EGL functions before init()

 * GL function table must not be initialized in constructor as
initialization may call eglGetProcAddress().

 * deinit()s called from destructors should touch EGL functions only if
there are live EGL objects (display teardown).

Change-Id: Ibfdbc0ff2280c3339c7c473d51fef5c88dbcc9fd