Don't GC-scan stack data redundantly.

Don't GC-scan stack data redundantly.
* src/alloc.c (Fgarbage_collect): When using stack scanning, don't
redundantly scan byte-code stacks, catchlist, and handlerlist.
* src/bytecode.c (BYTE_MAINTAIN_TOP): New macros.
(struct byte_stack): Only define `top' and `bottom' if used.
(mark_byte_stack): Only define if used.
(BEFORE_POTENTIAL_GC, AFTER_POTENTIAL_GC): Nullify if BYTE_MAINTAIN_TOP
is not set.
(Fbyte_code): Don't set `bottom' unless BYTE_MAINTAIN_TOP is set.
* src/lisp.h (BYTE_MARK_STACK): New macro.
(mark_byte_stack): Only declare if BYTE_MARK_STACK is set.
* src/term.c (OUTPUT_IF): Use OUTPUT.