test/hash: improve output for r/w test

test/hash: improve output for r/w test

The hash read-write autotest generates a lot of text, which is very dense
on the screen. Even the summary at the end is hard to follow as everything
is very compact. We can improve readability by highlighting the starts of
the various sections, and by indenting the values within subsections.

Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>