chore(Rakefile): tune JVM for closure compiler
chore(Rakefile): tune JVM for closure compiler

Using the client VM and forcing 32bit mode gives us huge perf boost.

before:

reali   0m8.173s
user    0m39.984s
sys     0m1.408s

after:

real    0m3.000s
user    0m12.687s
sys     0m0.852s

ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js,ggershoni/angular.js