Macro should end with a ;

Bug: angleproject:3976
Change-Id: I4aaa146464d9d7e6230a3de44c30cfd1179a89ae
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1864620
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Commit-Queue: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>