Remove unneccessary call to set_indices

ssa_l2 is already an L2 expression, its indices doesn't need to be reset.

Author: romainbrenguier

src/goto-symex/goto_symex_state.cpp

@@ -452,8 +452,7 @@ bool goto_symex_statet::l2_thread_read_encoding(
       source,
       symex_targett::assignment_typet::PHI);
 
-    // TODO: are we setting l2 indices of something that is already l2?
-    expr = set_indices<L2>(std::move(ssa_l2), ns).get();
+    expr = std::move(ssa_l2);
 
     a_s_read.second.push_back(guard);
     if(!no_write.op().is_false())