[turbofan] Introduce JSStackCheck operator.

src/compiler/ast-graph-builder.h

Index: src/compiler/ast-graph-builder.h
diff --git a/src/compiler/ast-graph-builder.h b/src/compiler/ast-graph-builder.h
index b26abbaee0f7a4dd4539f126f172fbbc85cb998a..0ce24652db3ad3aceb9fdb57e4e342499fb1cc60 100644
--- a/src/compiler/ast-graph-builder.h
+++ b/src/compiler/ast-graph-builder.h
@@ -260,9 +260,6 @@ class AstGraphBuilder : public AstVisitor {
   // Builders for binary operations.
   Node* BuildBinaryOp(Node* left, Node* right, Token::Value op);
 
-  // Builder for stack-check guards.
-  Node* BuildStackCheck();
-
   // Check if the given statement is an OSR entry.
   // If so, record the stack height into the compilation and return {true}.
   bool CheckOsrEntry(IterationStatement* stmt);