[lldb] Fix 'error: non-const lvalue...' caused by SWIG 4.1.0

Fix the failure caused by change in SwigValueWraper for C++11 and later
for improved move semantics in SWIG commit.

https://github.com/swig/swig/commit/d1055f4b3d51cb8060893f8036846ac743302dab
(cherry picked from commit f0a25fe0)