* fix decimal divide int issue

* correct cpp uts

* use const reference

Co-authored-by: Yuan <yuan.zhou@outlook.com>

Co-authored-by: Yuan <yuan.zhou@outlook.com>

…roject#266)

* change the UnsafeAppend to Append

* fix buffer builder in shuffle

shuffle builder use UnsafeAppend API for better performance. it
tries to reserve enough space based on results of last recordbatch,
this maybe not buggy if there's a dense recordbatch after a sparse one.

this patch adds below fixes:
- adds Reset() after Finish() in builder
- reserve length for offset_builder in binary builder

A further clean up on the reservation logic should be needed.

Signed-off-by: Yuan Zhou <yuan.zhou@intel.com>

Co-authored-by: Yuan Zhou <yuan.zhou@intel.com>