Model exceptional edges from call nodes in TurboFan.

src/compiler/operator.h

Index: src/compiler/operator.h
diff --git a/src/compiler/operator.h b/src/compiler/operator.h
index 616b4cf7afe178433d9db9436d458b4e8189d8d9..21f74eaf8565c21ce71a8ebb3d6d2cd86eb0358a 100644
--- a/src/compiler/operator.h
+++ b/src/compiler/operator.h
@@ -94,6 +94,10 @@ class Operator : public ZoneObject {
   int EffectOutputCount() const { return effect_out_; }
   int ControlOutputCount() const { return control_out_; }
 
+  static size_t ZeroIfNoThrow(Properties properties) {
+    return (properties & kNoThrow) == kNoThrow ? 0 : 2;
+  }
+
   static size_t ZeroIfPure(Properties properties) {
     return (properties & kPure) == kPure ? 0 : 1;
   }