[turbofan] Fix tail call optimization.

src/compiler/schedule.h

Index: src/compiler/schedule.h
diff --git a/src/compiler/schedule.h b/src/compiler/schedule.h
index 027a01dd4af03a9d46bdff6f52bed68672f5a1f5..37ce76299ed53858411f38493ee78275c0efeb61 100644
--- a/src/compiler/schedule.h
+++ b/src/compiler/schedule.h
@@ -37,6 +37,7 @@ class BasicBlock final : public ZoneObject {
     kBranch,      // Branch if true to first successor, otherwise second.
     kSwitch,      // Table dispatch to one of the successor blocks.
     kDeoptimize,  // Return a value from this method.
+    kTailCall,    // Tail call another method from this method.
     kReturn,      // Return a value from this method.
     kThrow        // Throw an exception.
   };
@@ -220,6 +221,9 @@ class Schedule final : public ZoneObject {
   // BasicBlock building: add a deoptimize at the end of {block}.
   void AddDeoptimize(BasicBlock* block, Node* input);
 
+  // BasicBlock building: add a tailcall at the end of {block}.
+  void AddTailCall(BasicBlock* block, Node* input);
+
   // BasicBlock building: add a return at the end of {block}.
   void AddReturn(BasicBlock* block, Node* input);