Capture/Replay: Generalize function splitting. We can use this to split up the replay function as well as very large setup functions. This will let us replay the gfxbench offscreen benchmarks directly. Bug: angleproject:5133 Change-Id: Ic24f25f2ab6821e68356a28a698cb84301e99be2 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2446896 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Courtney Goeltzenleuchter <courtneygo@google.com> Reviewed-by: Cody Northrop <cnorthrop@google.com>