Only allow one relayout with sync per sync request

If a new relayout occurs while in a sync, VRI will attempt another sync.
This is not intended so only allow one relayout request during a sync to
actually use blast sync

Test: Presubmit with shell transitions
Change-Id: Ic1211add59374ce82081bc88f6b2dfdd367438e3
Bug: 200285149
2 files changed