Remove deprecated primitive wrapper constructor usage

[mbien]

Primitive wrapper constructors like new Integer("5") are deprecated for removal.

[mbien]

this might no longer be a priority:
https://bugs.openjdk.org/browse/JDK-8354335

although even if the constructors would remain the object identity would be likely still gone, so the refactoring to valueOf() was likely still a useful step.

[neilcsmith-net]

Absolutely still a useful step, and probably just as much a priority IMO. Making sure we handle all the cases where we have behaviour that relies on object identity is still really important. This helps ensure we've done that. I'm not sure I like the plan for new not to mean new - it muddies the water too much.