move fallback in a level of nesting

vyper/codegen/module.py

@@ -169,13 +169,16 @@ def parse_regular_functions(
             external_seq.append(["assert", ["iszero", "callvalue"]])
             external_seq += nonpayable_funcs
 
+    # place fallback in same block as other external functions
+    # (consistency for external tools which parse our IR)
+    external_seq.append(["label", "fallback", ["var_list"], fallback_lll])
+
     # bytecode is organized by: external functions, fallback fn, internal functions
     # this way we save gas and reduce bytecode by not jumping over internal functions
     runtime = [
         "seq",
         func_init_lll(),
         ["with", "_calldata_method_id", ["mload", 0], external_seq],
-        ["label", "fallback", ["var_list"], fallback_lll],
     ]
     runtime.extend(internal_funcs)