[ReconstructType] Factor the giant switch out of VisitNode NFC
[ReconstructType] Factor the giant switch out of VisitNode NFC

Make the control flow clearer by factoring out the switch.  There was a
single key line burried under there where the node is popped.

Incidentally rename the lonely snake_case parameter to this functiong,
since we're modifying every line anyway.

khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift,khizkhiz/swift