dbg: introduce lj-bc, lj-func and lj-proto dumpers

This patch adds dumpers for a single bytecode instruction (`lj-bc`), as
well as for all bytecodes inside one function (`lj-func`) or prototype
(`lj-proto`). Its dump is quite similar to the -bl flag but also
reports types of register operands (`jmp`, `dst`, `str`, etc.).

For LLDB, the result from the `lookup_global()` method is wrapped to the
`lldb.value` object to make it more convenient. Also, it workarounds
several LLDB revisions in which this can't be done for the array
objects. See details in the corresponding comment.

Part of tarantool/tarantool#4808

Reviewed-by: Evgeniy Temirgaleev <e.temirgaleev@tarantool.org>
Reviewed-by: Sergey Bronnikov <sergeyb@tarantool.org>
Signed-off-by: Sergey Kaplun <skaplun@tarantool.org>

Author: Buristan