Set allowClearForRobustResourceInit to true on D3D9 backend,
which fixes clients report issues where unity web app throws
`Fail to create image surface` error on integrated-intel gpu
Bug: chromium:1011627, chromium:1017076
Change-Id: I733434123a8c34671b1a33b87017367baec5623c
TBR=geofflang@chromium.org
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1898701Reviewed-by: Shrek Shao <shrekshao@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>
