unittest_librbd is way too big - need to refactor?

Hi all, I am trying to build master on 32 bit ARM machine. cc1plus gives up with "virtual memory exhausted: Cannot allocate memory" when trying to build unittest_librbd with Release build type (not even Debug - so no debug symbols). I see cc1plus process grow to 3GB (maximum userspace available under Linux on 32 bit machines) and then just bailing out (presumably when it is unable to alloc more memory). unittest_librbd consists out of number test suites and running them all together is a tall order for 32 bit machines. In fact TestMigration is so big so it cannot successfully pass without bad_alloc even if it is built on 64 bit machine for 32 bit system. So I suggest to break unittest_librbd to number of separate test suites to avoid issues with building and test execution. I am willing to contribute by refactoring it but want to get devs view of the problem before doing so. Regards, Vladimir