Reorganized the sanitizer-related flags
Reorganized the sanitizer-related flags

To reflect the constraint that sanitizers are not compatible with each other.

anirajk/RAMCloud,anirajk/RAMCloud,utah-scs/RAMCloud,jblomer/ramcloud,SMatsushi/RAMCloud,jblomer/ramcloud,utah-scs/RAMCloud,SMatsushi/RAMCloud,anirajk/RAMCloud,utah-scs/RAMCloud,anirajk/RAMCloud,SMatsushi/RAMCloud,utah-scs/RAMCloud,jblomer/ramcloud,SMatsushi/RAMCloud,SMatsushi/RAMCloud,SMatsushi/RAMCloud,utah-scs/RAMCloud,utah-scs/RAMCloud,jblomer/ramcloud,jblomer/ramcloud,anirajk/RAMCloud,anirajk/RAMCloud,jblomer/ramcloud