[tests] separate large tests to lower peak memory (#1989)
[tests] separate large tests to lower peak memory (#1989)

After Travis updated its environment, Travis fails distcheck due to insufficient memory. Although OpenThread itself doesn't use much memory, the address sanitizer does.

This commit separates large scale test cases to lower peak memory usage when running certification tests on Travis.
LeZhang2016/openthread,lanyuwen/openthread,abtink/openthread,erja-gp/openthread,pvanhorn/openthread,xiaom-GitHub/openthread,vaas-krish/openthread,mszczodrak/openthread,pvanhorn/openthread,turon/openthread,pvanhorn/openthread,JakubBrachTieto/openthread,lanyuwen/openthread,vaas-krish/openthread,xiaom-GitHub/openthread,bukepo/openthread,LeZhang2016/openthread,erja-gp/openthread,turon/openthread,LeZhang2016/openthread,JakubBrachTieto/openthread,openthread/openthread,lanyuwen/openthread,aeliot/openthread,pvanhorn/openthread,chshu/openthread,fbsder/openthread,fbsder/openthread,xiaom-GitHub/openthread,bukepo/openthread,srickardti/openthread,chshu/openthread,lanyuwen/openthread,JakubBrachTieto/openthread,aeliot/openthread,openthread/openthread,georgecpr/openthread,mszczodrak/openthread,librasungirl/openthread,openthread/openthread,lanyuwen/openthread,chshu/openthread,gandreello/openthread,jwhui/openthread,gandreello/openthread,georgecpr/openthread,LeZhang2016/openthread,LeZhang2016/openthread,georgecpr/openthread,srickardti/openthread,georgecpr/openthread,fbsder/openthread,gandreello/openthread,mszczodrak/openthread,pvanhorn/openthread,jwhui/openthread,jwhui/openthread,abtink/openthread,xiaom-GitHub/openthread,georgecpr/openthread,erja-gp/openthread,openthread/openthread,aeliot/openthread,mszczodrak/openthread,chshu/openthread,fbsder/openthread,erja-gp/openthread,mszczodrak/openthread,xiaom-GitHub/openthread,JakubBrachTieto/openthread,fbsder/openthread,LeZhang2016/openthread,turon/openthread,lanyuwen/openthread,fbsder/openthread,vaas-krish/openthread,xiaom-GitHub/openthread,vaas-krish/openthread,srickardti/openthread,jwhui/openthread,bukepo/openthread,chshu/openthread,librasungirl/openthread,mszczodrak/openthread,aeliot/openthread,librasungirl/openthread,erja-gp/openthread,abtink/openthread,vaas-krish/openthread,gandreello/openthread,aeliot/openthread,chshu/openthread,georgecpr/openthread,erja-gp/openthread,srickardti/openthread,bukepo/openthread,librasungirl/openthread,abtink/openthread,JakubBrachTieto/openthread,pvanhorn/openthread,aeliot/openthread,gandreello/openthread,turon/openthread,gandreello/openthread,vaas-krish/openthread,JakubBrachTieto/openthread