Add comment for debugging only

Author: jkeenan

t/op/goto.t

@@ -733,7 +733,7 @@ is \sub :lvalue { goto d; ${*{scalar(do { d: \*foo })}} }->(), \$foo,
    'goto into rv2sv, rv2gv and scalar';
 is sub { goto e; $#{; do { e: \@_ } } }->(1..7), 6,
    'goto into $#{...}';
-is sub { goto f; prototype \&{; do { f: sub ($) {} } } }->(), '$',
+is sub { goto f; prototype \&{; do { f: sub ($) {} } } }->(), '$', # EXEMPT
    'goto into srefgen, prototype and rv2cv';
 is sub { goto g; ref do { g: [] } }->(), 'ARRAY',
    'goto into ref';