The top z gap should be split if it's too large.
Also we use same logic for both synced and independent support layer.
jira: STUDIO-7232
github: #4191
Change-Id: Idca792e8fa51a83c2a09441ecac64d40b91d6390
(cherry picked from commit c262a7ea137db09e453c157115b3d5417a32886d)