[jvm-packages]add feature size for LabelPoint and DataBatch (#5303)

* fix type error

* Validate number of features.

* resolve comments

* add feature size for LabelPoint and DataBatch

* pass the feature size to native

* move feature size validating tests into a separate suite

* resolve comments

Co-authored-by: fis <jm.yuan@outlook.com>

src/data/simple_dmatrix.cc

@@ -125,6 +125,7 @@ SimpleDMatrix::SimpleDMatrix(AdapterT* adapter, float missing, int nthread) {
   } else {
     info_.num_col_ = adapter->NumColumns();
   }
+
   // Synchronise worker columns
   rabit::Allreduce<rabit::op::Max>(&info_.num_col_, 1);