Calling eglMakeCurrent between different D3D9 contexts could lead to
state sync bugs. This fixes the problem by ensuring all internal
state is dirtied between makeCurrent calls.

This bug turned up when refactoring the tests to run multiple Contexts
with the same EGLDisplay.

Bug: angleproject:3261
Change-Id: Ic91e1af8b2615e7e7e0d0faabeb533d075ea2e91
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1531534
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>