Move some code in the register assignment case that only needs to happen if we spill out of the fast path.  The scan of active_ and the calls to updateSpillWeights don't need to happen unless a spill occurs.  This reduces debug llc time of kc++ with ppc from 187.3s to 183.2s.
Move some code in the register assignment case that only needs to happen if
we spill out of the fast path.  The scan of active_ and the calls to
updateSpillWeights don't need to happen unless a spill occurs.  This reduces
debug llc time of kc++ with ppc from 187.3s to 183.2s.


git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@22971 91177308-0d34-0410-b5e6-96231b3b80d8

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