refactor($parse): don't use bind-once interceptor for non-bind-once expressions

Side-effects:
  - Logic for allOrNothing watches now lives in $intercept rather than $parse

Closes #9958
I'm not misunderstanding it, what I'm understanding is that it was a stupid thing to begin with. We don't need hacks to improve performance, what we need is better algorithms, and better VM implementations, to improve performance.