Fix shuffle test errors

[kmaehashi]

Currently some shuffle tests are failing.

• CUDA installation error (installation to unsupported OS) Only run tests on supported combinations #535
• CentOS 6 requires special installer for CUDA 10.1+ Avoid testing CUDA 10.1 on CentOS 6 #538
• SciPy import error import scipy fails because of ImportWarning #534
• 4 different CuPy code issues (daily_master_cupy-shuffled) -- must be reviewed separately
  • Fix for NumPy 1.14.x compatibility cupy/cupy#2544 TestIndexing
  • Workaround bug in NumPy 1.12.x or earlier cupy/cupy#2545 test_shares_memory
  • ...
• cuDNN 6 specific error (tolerance error in TestConvolution2D, TestDeconvolutionND)
• NCCL_ERROR_UNHANDLED_CUDA_ERROR (c.f. Do not test against Python 2 / 3.4 for master branch #523)
• protobuf-cpp-3 build error (python 3.7)

The following result is the variation as of 2019-10-15. (the test combination has changed now)

daily_stable_cupy-shuffled

#11 CUDA installation

daily_stable_chainer-shuffled

#1 cudnn 6 error
#2 cudnn 6 error
#3 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#5 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#6 CUDA installation
#9 CUDA installation
#11 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#13 protobuf-cpp-3 build error
#15 CUDA installation
#17 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#18 protobuf-cpp-3 build error
#19 cudnn 6 error
#20 cudnn 6 error

daily_master_chainer-shuffled

#0 protobuf-cpp-3 build error
#1 cudnn 6 error
#2 cudnn 6 error
#4 cudnn 6 error
#5 protobuf-cpp-3 build error
#6 CUDA installation
#8 CUDA installation
#10 cudnn 6 error
#12 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#13 CUDA installation
#15 CUDA installation
#16 NCCL_ERROR_UNHANDLED_CUDA_ERROR
#17 CUDA installation
#18 cudnn 6 error
#19 protobuf-cpp-3 build error
#20 cudnn 6 error

daily_master_cupy-shuffled

#0 CUDA installation
#2 Floating point exception in test
#3 test_shares_memory
#4 test_shares_memory
#6 CUDA installation 
#7 TestIndexing
#8 TestIndexing
#9 CUDADriverError
#10 TestIndexing
#11 test_shares_memory
#12 TestIndexing
#14 test_shares_memory
#15 CUDA installation
#16 CUDADriverError
#17 TestIndexing