Fix trace logging in Debug. - fix crash when logging an invalid context - output to trace even when platform logging is on Bug: angleproject:3815 Change-Id: I725f5728e1d839e3d8458579ad1958cb775d9ecf Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1769505 Reviewed-by: Jamie Madill <jmadill@chromium.org> Reviewed-by: Corentin Wallez <cwallez@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>