serializer: remove duplicate of lua serializer

This patch fixes a bug found by the ASAN instrumentation of LuaJIT
allocator [1]. The problem is using a Lua serializer object that has
been cleaned up by GC.

The crash occurs when executing `tarantool> \set output lua`.

Failing tests:
 - ./test/app-luatest/gh_7031_configure_eos_in_lua_console_test.lua
 - ./test/app-tap/console.test.lua
 - ./test/box/push.test.lua
 - ./app-tap/console_lua.test.lua
 - ./app-luatest/varbinary_test.lua

The `serializer_lua` static member is removed from
`src/box/lua/serialize_lua.c` along with `serializer_lua_init`,
because it is not used by any function other than `serializer_lua_init`,
which is not needed now too.

[1]: Issue #10231

Closes #10177 (this issue is a duplicate of #7404)

NO_TEST=rely on existing tests
NO_CHANGELOG=codehealth
NO_DOC=codehealth

(cherry picked from commit 830f27bbaf94dadcacc66a7f543e0e5feec3988d)