Some dEQP tests call eglTerminate twice on the same display and cause crashes.

BUG=angleproject:2546

Change-Id: I8a13d00fd03692b3b24dee4813c245d83ea00862
Reviewed-on: https://chromium-review.googlesource.com/1060335Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>