ztest API Migration: lib/cmsis_dsp

Migrate some of the unit tests at `lib/cmsis_dsp`
to the new ztest API:

  * lib/cmsis_dsp/basicmath
  * lib/cmsis_dsp/bayes
  * lib/cmsis_dsp/complexmath
  * lib/cmsis_dsp/distance
  * lib/cmsis_dsp/fastmath

`lib/cmsis_dsp/common/test_common.h` has been adapted to use the new
ztest API for the test variant macros, when enabled.

Signed-off-by: Tristan Honscheid <honscheid@google.com>