tests: Remove unnecessary .get() from RAII objects Bug: chromium:40942995 Change-Id: I82509869bce3ad8f51811188fe04267f2de04786 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5370904 Reviewed-by: Geoff Lang <geofflang@chromium.org> Commit-Queue: Shahbaz Youssefi <syoussefi@chromium.org>