Adding properties to the user test targets to prevent parallel compiles, as we already did with the main test target.

Patch by: jlabanca
Review by: rjrjr (TBR)



git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@6460 8db76d5a-ed1c-0410-87a9-c151d255dfc7