Make error handling and debug messages thread safe Bug: angleproject:8135 Bug: angleproject:8224 Change-Id: I1527b6a02d917724034873b5206f2006ae0eaf05 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4678284 Reviewed-by: Geoff Lang <geofflang@chromium.org> Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: Charlie Lao <cclao@google.com> Auto-Submit: Shahbaz Youssefi <syoussefi@chromium.org>