[lldb/lua] Force Lua version to be 5.3

Due to CMake cache, find_package in FindLuaAndSwig.cmake
will be ignored. This commit adds EXACT and REQUIRED flags
to it and removes find_package in Lua ScriptInterpreter.

Signed-off-by: Siger Yang <sigeryeung@gmail.com>

Reviewed By: tammela, JDevlieghere

Differential Revision: https://reviews.llvm.org/D108515