fix(testability): findBindings should escape binding expressions before ...

...performing regexp

Move the function to escape regexps to Angular.js, fix the link, and use it in
the $$testability service.

See #9595
I think this should be `false` here. To tell JSHint that in general this is readonly constant.
That is why it is overridden in Angular.js below to `true` where we actually set the value of it.