Fixes #4713: Java-ompi: slice methods fix

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r31943 [[BR]]
Java - slice methods: set buffer limit to its capacity before change its position
Fixes #4715: Move r31985, r31987, r32013 to v1.8 branch (Fix MPI_Alltoallv in coll/tuned)

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r31985 [[BR]]
Fix MPI_Alltoallv in coll/tuned.

Correctly handle the corner case in MPI_Alltoallv when
some tasks have no data to transfer and some other tasks
do have data to transfer.

This test case is covered in ibm/collective/alltoallv_somezeros
from the ompi-tests repo.

cmr=v1.8.2:reviewer=bosilca

r31987 [[BR]]
Cleanup the utilities functions in tuned.

r32013 [[BR]]
Fix MPI_Alltoallv in coll/tuned

This changeset :
- always call the low/level implementation for :
  * MPI_Alltoallv
  * MPI_Neighbor_alltoallv
  * MPI_Alltoallw
  * MPI_Neighbor_alltoallv
- fix mca_coll_tuned_alltoallv_intra_basic_inplace
  so zero size types are correctly handled

cmr=v1.8.2:reviewer=bosilca:ticket=4715