Capture/Replay: Only create active secondary contexts in MEC This finalized the fix attempted in b432c84c2b8cb6d20873e2b33b6684bee76db90d Capture/Replay: Fix collecting the initialized contexts Bug: angleproject:7858 Change-Id: Ie2bbcdb3f23fe4970ce3a9bb46df6f60fe6c8ab6 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/4084926 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Gert Wollny <gert.wollny@collabora.com>