When injecting symbols, do not rely on the last Module:
When injecting symbols, do not rely on the last Module:

With llvm9, the module ptr gets reset upon emission.
Instead, just look for the symbol in the JIT - where it should be found,
as Init() is injecting it there, and we want to find *that* symbol,
not the one from the binary.

Fixes `CodeUnloading/AtExit.C` cling test.

olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root,olifre/root