In the case where command graph is disabled, we don't need to call
appendToStartedRenderPass().

Bug: angleproject:4029
Change-Id: I9b9d1ad666a903fcb63ab394944cfe7adb836a08
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2065708Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Tobin Ehlis <tobine@google.com>