Add vector exp2/exp2f and input files to libmvec microbenchmark.
libmvec-exp2-inputs:
90% Normal random distribution
range: (-1022.0, 1024.0)
mean: 0.0
sigma: 16.0
10% uniform random distribution in range (-1000.0, 1000.0)
libmvec-exp2f-inputs:
90% Normal random distribution
range: (-126.0f, 128.0f)
mean: 0.0f
sigma: 8.0f
10% uniform random distribution in range (-100.0f, 100.0f)
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>