Update inaccurate error string. Noticed when working on the traces. Bug: angleproject:4845 Change-Id: I954851bc739e41ce84047eaf5e0dc4c8bcf57199 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2329832 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>