leave_scope(): eliminate a couple of local vars

leave_scope(): eliminate a couple of local vars

Remove svp and i from the main loop and only declare them in the
inner scopes that require them. Where values get passing around in
goto restore_sv/restore_svp, pass the value in an unused a0/a2 var
instead.

Also eliminate the one use of the 'type' var within the loop - that way
the compiler doesn't have to hang on the value when executing the switch.

Makes the object code a bit smaller.