hash_value: fix hashing of trampolines

Two trampolines are equal if there are the same function and created in
the same scope. This patch makes sure hash_svalue is compatible and
trampolines can now be reliably used as hash keys.

Thanks to Stefan Gluszek <stefang@opera.com> for reporting this issue.
Backend: Added some linebreaks.

Also rephrases some fatal errors.
Backend: Make a few more internal functions static.

This makes several CFRUNLOOP-related functions static.