Add a test for new `view` command

- includes a SAM file with one read for each of the 1000 possible
  flag-field values allowed by HTSJDK’s SAM parsing code.
- bonus: includes `make-flag-values-sam.py` script used to generate the
  aforementioned SAM file!
- concern: ViewSuite test takes about 30s to run on my laptop; how much
  do we care about test-running latency? Is there an obviously quicker
  way to run a similar test?