This perf test measures the GPU time spent uploading texture data.

Bug: angleproject:2361
Change-Id: I62fcf0e893fdcc9826a083e23320051a69559fab
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1529922
Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>