BLD: various test_perf fixes

[ghost]

• The git ref parsing didn't handle annotated tags well, returning a bad hash
  if you tried test_perf -t HEAD -b v0.13.0 and got a weird error, fixed. (git weirdness, fyi @cpcloud)
• try to Disable frame_expand_repr when printing stats, pasting results for comparison is much easier
  that way.
• Added --temp-dir to name a specific (rather then randomized) scratch directory for vbench,
  the randomized temp. dir was preventing ccache from doing it's job. Highly recommended
  that you always invoke test_perf with a consistent --temp-dir my-benching-dir. This took down
  the comparative runs from 5 minutes to less then 60 seconds on my box. cc @jreback, @yarikoptic.

xref #6199