CPUDispatch- allow out of line member definitions

ICC permits this, and after some extensive testing it looks like we can
support this with very little trouble.  We intentionally don't choose to
do this with attribute-target (despite it likely working as well!)
  because GCC does not support that, and introducing said
  incompatibility doesn't seem worth it.

GitOrigin-RevId: 92aba5ae49a6970c43bead0afd1e52c83fe44e6e
3 files changed