[turbofan] Replace uninitialized JSConstruct nodes with SOFT deopt.

src/compiler/js-call-reducer.h

Index: src/compiler/js-call-reducer.h
diff --git a/src/compiler/js-call-reducer.h b/src/compiler/js-call-reducer.h
index 238ca77ab9b4a1b46d9db428580a1b2768ffdc52..c9fcd87db84a9bcd5fdc25a04eccc8e815bbcf8e 100644
--- a/src/compiler/js-call-reducer.h
+++ b/src/compiler/js-call-reducer.h
@@ -7,6 +7,7 @@
 
 #include "src/base/flags.h"
 #include "src/compiler/graph-reducer.h"
+#include "src/deoptimize-reason.h"
 
 namespace v8 {
 namespace internal {
@@ -70,6 +71,8 @@ class JSCallReducer final : public AdvancedReducer {
   Reduction ReduceJSCallWithSpread(Node* node);
   Reduction ReduceReturnReceiver(Node* node);
 
+  Reduction ReduceSoftDeoptimize(Node* node, DeoptimizeReason reason);
+
   Graph* graph() const;
   JSGraph* jsgraph() const { return jsgraph_; }
   Isolate* isolate() const;