L1 turn on clone merge procedure

Turn back on clone merge procedure to prevent clone tracks, which exceed 10 % when MVD detector is in the setup for event-by-event reconstruction. It was turned off because for time-based case (without MVD) it is not improving performance, but takes significant time.

changed milestone to %APR21

assigned to @se.gorbunov

assigned to @f.uhlig and unassigned @se.gorbunov

approved this merge request

I assigned it to @f.uhlig, because the MR should go to the release.

Dear @se.gorbunov, @v.akishina,

you have been identified as code owner of at least one file which was changed with this merge request.

Please check the changes and approve them or request changes.

added CodeOwners label

mentioned in merge request !303 (merged)

merged