inlining: Mark inserted PiNodes for refinement

For extended lattice elements, the type of the resulting PiNode can end
up imprecise when `tmeet(argextype(argex), mft) ⊑ mft`

base/compiler/ssair/inlining.jl

@@ -565,8 +565,9 @@ function ir_inline_unionsplit!(compact::IncrementalCompact, idx::Int, argexprs::
                 (isa(argex, SSAValue) || isa(argex, Argument)) || continue
                 aft, mft = fieldtype(atype, i), fieldtype(mtype, i)
                 if !(aft <: mft)
+                    flag = IR_FLAG_REFINED
                     argexprs′[i] = insert_node_here!(compact,
-                        NewInstruction(PiNode(argex, mft), mft, line))
+                        NewInstruction(PiNode(argex, mft), mft, NoCallInfo(), line, flag))
                 end
             end
         end