add a dump method to TreeViews (#17965)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/17965
ghimport-source-id: 0d3d6340141d8413ce524a8d8ed0d308854ee7ef
Stack:
* (to be filled)
Also added it to the python bindings. Not for any particular reason,
just because otherwise the function gets elided (even in debug mode!)
and thus can't be called from the debugger
Reviewed By: eellison
Differential Revision: D14442654
fbshipit-source-id: 2868bb32ccb80b04f9483883faa702f63a7948bf
