Make fewer calls to currentTimeMillis

To eliminate some noise from profiles.
Optimization: use sameLength rather than a.size == b.size
Optimization: Avoid Nil#equals on really hot paths
Optimize findMember

Call baseClasses exactly once, rather 1-2 times.
Use fields rather than accessors to clean up profile results

Not sure why my profiler was insisting the calls from `compileUnitsInternal`
to `globalPhase` were taking forever, but I've complied by using getField
instead.

The other places are both very hot, so we might as well start out with field
access rather than waiting for HotSpot to inline the accessors.
Optimize findMember

Avoid virtual call to isEmpty
Optimize rawInfo

Hoist out call to outer$