Define operator new/delete for smobs (issue 551390047 by address@hidden)

[dak]

That seems weird for me.  The topic states "this provides a way to run
LilyPond with Guile 2.2" but garbage collection with Guile 2.2 works out
of the box already.  This patch only causes extra work and will slow
down garbage collection further.

The only way in which it could make sense is if in return some other GC
hooks and/or work would be disabled.

https://codereview.appspot.com/551390047/