create galera buildbot ASAN/UBSAN builder

A UBSAN/ASAN built galera image will be able to perform some checking to/from its interface with the server.

Base work done on the galera side to ensure it can pass its own tests:

• https://github.com/MariaDB/galera/pull/38
• https://github.com/MariaDB/galera/pull/39 Transform the logging scheme to use wsrep_api types/constants
• https://github.com/MariaDB/galera/pull/40 UndefinedBehaviorSanitizer: misaligned-pointer-use mmh3
• https://github.com/MariaDB/galera/pull/41

The function-type-mismatch of 39 will restrict UBSAN tests until fixed. Others are test case only (40 is making some assumptions that may/may not be true)