Revert "btree: enable and fix space opt issue"
Revert "btree: enable and fix space opt issue"

SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale,SanDisk-Open-Source/zetascale