test_suite: refactoring
test_suite: fix: count -> $count
test_suite: decrease amount of bytes written by dd per loop

On system with very slow I/O this avoids exceeding timeouts
test_suite: typo
test_suite: add test_cases to build the mars module and install a new kernel on the test systems
test_suite: after split brain resolution wait for device to appear
test_suite: doc: Howto understand what a test does