[ORC][examples] Add missing EPCIndirectionUtils::cleanup call.

Clients are required to make this call prior to destroying the object. Adding
the missing call fixes an assertion that was triggering at program termination
time in the LLJITWithExecutorProcessControl example.

Author: lhames

llvm/examples/OrcV2Examples/LLJITWithExecutorProcessControl/LLJITWithExecutorProcessControl.cpp

@@ -194,5 +194,8 @@ int main(int argc, char *argv[]) {
   outs() << "---Result---\n"
          << "entry(" << argc << ") = " << Result << "\n";
 
+  // Destroy the EPCIndirectionUtils utility.
+  ExitOnErr(EPCIU->cleanup());
+
   return 0;
 }