Shrink Gauss-Seidel test matrices

[brian-kelley]

Prevent tests from timing out (#547, and Trilinos #6464). Spot checks running...

[brian-kelley]

Spot checks are good:
#######################################################
PASSED TESTS
#######################################################
intel-16.4.258-Pthread-release build_time=708 run_time=384
intel-16.4.258-Pthread_Serial-release build_time=1017 run_time=775
intel-16.4.258-Serial-release build_time=692 run_time=377
intel-17.2.174-OpenMP-release build_time=875 run_time=183
intel-17.2.174-OpenMP_Serial-release build_time=1213 run_time=516
intel-17.2.174-Pthread-release build_time=801 run_time=344
intel-17.2.174-Pthread_Serial-release build_time=1112 run_time=673
intel-17.2.174-Serial-release build_time=767 run_time=322
intel-18.2.199-OpenMP-release build_time=877 run_time=185
intel-18.2.199-OpenMP_Serial-release build_time=1229 run_time=514
intel-18.2.199-Pthread-release build_time=656 run_time=361
intel-18.2.199-Pthread_Serial-release build_time=940 run_time=680
intel-18.2.199-Serial-release build_time=651 run_time=316

#######################################################
PASSED TESTS
#######################################################
cuda-9.2.88-Cuda_OpenMP-release build_time=488 run_time=367
cuda-9.2.88-Cuda_Serial-release build_time=509 run_time=399
gcc-6.4.0-OpenMP_Serial-release build_time=197 run_time=180
gcc-7.2.0-OpenMP-release build_time=129 run_time=68
gcc-7.2.0-OpenMP_Serial-release build_time=195 run_time=174
gcc-7.2.0-Serial-release build_time=118 run_time=98
ibm-16.1.0-Serial-release build_time=481 run_time=138
#######################################################
FAILED TESTS
#######################################################
ibm-16.1.0-OpenMP-release (test failed)
ibm-16.1.0-OpenMP_Serial-release (test failed)

Only failures (were fixed this afternoon):
The following tests FAILED:
1 - blas_openmp (Failed)
5 - blas_serial (Failed)