Ensure that closure cfg is built before running LVA on them.

* We need to redo some of the dependency business, but for now,
  this does the trick.

* Discovered by running rubyspecs with passes:
  OptimizeTempVarsPass,LocalOptimizationPass,DeadCodeElimination,LinearizeCFG
Fix default JIT passes in IRManager

* Accidentally left behind in an older commit.