improve testsuite to test larger problem sizes

[juliantaylor]

given the many crashes you find in openblas when you use problem sizes bigger than a couple MB (e.g. gh-173, gh-154, gh-174), the testsuite should be improved to test all operations with problems larger than its internal buffer size.
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[xianyi]

Hi,

We created a project https://github.com/rdcps/BLAS-Tester to test BLAS. However, we didn't test the case about very big M and small N .

Xianyi