Deparse: Introduce subs after they are defined

This is wrong:

$ perl -MO=Deparse -e 'foo(); sub foo { foo() } foo()'
foo();
sub foo {
    foo ;
}
foo ;
-e syntax OK

You need foo() inside sub foo{}.  The parentheses are not optional.
The sub was being introduced (Deparse was recording is as declared)
just before the definition was emitted.