TST fix broken fast_dot test

Due to a misspelling ("get_blas" vs. "get_blas_funcs") and a bare except
clause, the tests weren't actually being run.
COSMIT friendlier output from faster NMF benchmark

Tolerance lowered to make it run in reasonable time; see #2537.
ENH micro-optimize NMF inner loop

Also fixed the random seed on the example.