change the javelin guests to be smaller

Creating 2 surviving resources as m1.small and m1.medium means locking
up 6GB of ram in surviving guests, which is *way* too much to
consistently work.

Tune this back down to m1.tiny and m1.micro.

Closes-Bug: #1398074

Change-Id: Ia9d679d82ffae951273f62c7beee67007b2ad080