Don't call {begin|end}DebugUtilsLabelEXT() when not enabled The ContextVk::handleDirtyEventLogImpl() and ContextVk::endEventLog() methods called the {begin|end}DebugUtilsLabelEXT() methods when the VK_EXT_debug_utils extension is not enabled. This manifests when enabling/using VVL stand-alone (i.e. when the the debug-utils extension is not also present). Bug: b/183133198 Change-Id: I043b174d457a8796831184c092661f24b33c1db4 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2821943 Commit-Queue: Ian Elliott <ianelliott@google.com> Reviewed-by: Cody Northrop <cnorthrop@google.com> Reviewed-by: Tim Van Patten <timvp@google.com>