x86-64: Add vector tanh/tanhf to libmvec microbenchmark

x86-64: Add vector tanh/tanhf to libmvec microbenchmark

Add vector tanh/tanhf and input files to libmvec microbenchmark.

libmvec-tanh-inputs:
  90% Normal random distribution
  range: (-19.0, 19.0)
  mean: 0.0
  sigma: 2.0
  10% uniform random distribution in range (-16.0, 16.0)

libmvec-tanhf-inputs:
  90% Normal random distribution
  range: (-10.0f, 10.0f)
  mean: 0.0f
  sigma: 2.0f
  10% uniform random distribution in range (-8.0f, 8.0f)

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>