Fix undefined behavior in ll2string().

The bug was found by @CAFxX, thanks!
See issue #1940.
INIT
[+] v8 make
[=] v8.cpp
[+] needed changes for working in extern "C" block...
[=] hello world
[*] Makefile
[=] hello world (jsCommand)
[=] JSON.stringify result
[+] made shortcuts for future cashing
[=]
[=] Redis.Call (without parsing of response)
[+] parse reply from redis
[=]
[+] check number of arguments
[=]
[=]
Revert "[=]"

This reverts commit 432cad6fb1dafbc0017062e8aca493288727526c.
[+] jsCommandPersistent (can be used for caching)
[=] prettify JSON