[CI] clean out the split rendering handling parts from ci config
- Related issues: #1114 (closed)
- Requested reviewers: @pihlajakuja @tamarapu
Reason why this change is needed
- Split rendering switches are active by default and about to be accepted. No need for special build jobs or enabling the switch
Description of the change
- Remove the split rendering build jobs and the enable-split-rendering anchor
Affected operating points
- Nothing, CI only.