LightGBM

reduce the buffer when using high dimensional data in distributed mode. (#2485)

* reduce the buffer when using high dimensional data in distributed mode.

* Update dataset_loader.cpp

* refix

* typo

* fix number of bin accumulation.

* avoid overflow

* fix warning

* efficient solution.

* Update dataset.h

* fix bin count output

* fix warning

* bug in dist number of feature check

* fix possible edge case

* Update dataset.cpp

* possible bug fix

* fix