Speed up AngleAxisRotatePoint.
Speed up AngleAxisRotatePoint.

This leads to a ~11% speedup on my mac using clang.

Based on suggestions by Thad Hughes.

Change-Id: If8495c8de6e28f63fb065e35bd6f382dd9fcbbea

stonier/ceres_solver,kartikkumar/ceres-solver,stonier/ceres_solver,timfel/ceres-bin,whuaegeanse/ceres-solver,entylop/ceres-solver,whuaegeanse/ceres-solver,ikoruk/ceres-solver,kartikkumar/ceres-solver,DougFirErickson/ceres-solver,timfel/ceres-bin,entylop/ceres-solver,ikoruk/ceres-solver,ysonggit/ceres-solver,ikoruk/ceres-solver,DougFirErickson/ceres-solver,whuaegeanse/ceres-solver,kartikkumar/ceres-solver,DougFirErickson/ceres-solver,ysonggit/ceres-solver,whuaegeanse/ceres-solver,DougFirErickson/ceres-solver,timfel/ceres-bin,ikoruk/ceres-solver,timfel/ceres-bin,stonier/ceres_solver,entylop/ceres-solver,entylop/ceres-solver,ysonggit/ceres-solver,kartikkumar/ceres-solver,ikoruk/ceres-solver,stonier/ceres_solver,ysonggit/ceres-solver