move constraint creation out of try context

mythril/analysis/modules/external_calls.py

@@ -108,7 +108,6 @@ def _analyze_state(state):
 
 def _is_precompile_call(global_state: GlobalState):
     to = global_state.mstate.stack[-2]  # type: BitVec
-    try:
     constraints = copy(global_state.mstate.constraints)
     constraints += [
         Or(
@@ -116,6 +115,8 @@ def _is_precompile_call(global_state: GlobalState):
             to > symbol_factory.BitVecVal(16, 256),
         )
     ]
+
+    try:
         solver.get_model(constraints)
         return False
     except UnsatError: