Remove IsStreamingIndexData from DrawCallNeedsTranslation since
IsStreamingIndexData is only needed for drawElementsIndirect for fast path.

This change gives about a 4% improvement on the drawElements benchmark for
the D3D11 backend with the null driver.

BUG=angleproject:1155

Change-Id: Ife2a9748f6b6fe9bc1f3a67c96672ab941a89d44
Reviewed-on: https://chromium-review.googlesource.com/717946Reviewed-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Commit-Queue: Geoff Lang <geofflang@chromium.org>