[turbofan] Narrow type of Phis during JSTypedLowering.

src/compiler/js-typed-lowering.h

Index: src/compiler/js-typed-lowering.h
diff --git a/src/compiler/js-typed-lowering.h b/src/compiler/js-typed-lowering.h
index 35c397fb888863d34192c75ffa42213620e3da3c..7673ad3bbe8d5ac087c8e2a9eb0028e3cff3421c 100644
--- a/src/compiler/js-typed-lowering.h
+++ b/src/compiler/js-typed-lowering.h
@@ -80,6 +80,7 @@ class JSTypedLowering final : public AdvancedReducer {
   Reduction ReduceLoadField(Node* node);
   Reduction ReduceNumberRoundop(Node* node);
   Reduction ReduceSelect(Node* node);
+  Reduction ReducePhi(Node* node);
   Reduction ReduceNumberBinop(Node* node);
   Reduction ReduceInt32Binop(Node* node);
   Reduction ReduceUI32Shift(Node* node, Signedness signedness);