Fix input rank-match comparison, --no-ref-model flag, no test list

- Fixed input shape/expected input shape mismatches
  when due to a missing batch dimension.
- Return from run_test() immediately after running compiler
  when --no-ref-model is set.  This avoids doing result
  comparisons on results that were never generated.
- Exit gracefully when no tests are specified instead of
  throwing TypeError on iterating NoneType

Signed-off-by: Jared Smolens <jared.smolens@arm.com>
Change-Id: I91d2c24fd60aa1cf8b3755894030ff14f1371ed0