tests/kms_atomic_transition: Convert tests to dynamic

Convert the existing subtests to dynamic subtests at pipe/output
level. And create an array of structures to populate subtests to
avoid code duplication.

This patch will also sanitize the system state before starting the
subtest with igt_display_reset().

V2:
- Fix cleanup part

Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
Reviewed-by: Karthik B S <karthik.b.s@intel.com>