This crash could occur when saving and loading a program with UBO
bindings that was never used in a draw operation. The fix is to
ensure the D3DLinkedUniforms are properly initialized before we
save the program binary.

BUG=angleproject:1637

Change-Id: I9691e375d19dc628f34f351ae94b68bd0f2f76b8
Reviewed-on: https://chromium-review.googlesource.com/422665
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>