[turbofan] Introduce JSStackCheck operator.

src/compiler/ast-graph-builder.cc

Index: src/compiler/ast-graph-builder.cc
diff --git a/src/compiler/ast-graph-builder.cc b/src/compiler/ast-graph-builder.cc
index e87ca786b19775e1dac0d88e370b1ac7d75bb6f1..80d7e046cb7db3496154d9ae810f7cd97446ff6b 100644
--- a/src/compiler/ast-graph-builder.cc
+++ b/src/compiler/ast-graph-builder.cc
@@ -508,7 +508,7 @@ void AstGraphBuilder::CreateGraphBody() {
   VisitDeclarations(scope->declarations());
 
   // Build a stack-check before the body.
-  Node* node = BuildStackCheck();
+  Node* node = NewNode(javascript()->StackCheck());
   PrepareFrameState(node, BailoutId::FunctionEntry());
 
   // Visit statements in the function body.
@@ -2965,21 +2965,6 @@ Node* AstGraphBuilder::BuildBinaryOp(Node* left, Node* right, Token::Value op) {
 }
 
 
-Node* AstGraphBuilder::BuildStackCheck() {
-  IfBuilder stack_check(this);
-  Node* limit = BuildLoadExternal(
-      ExternalReference::address_of_stack_limit(isolate()), kMachPtr);
-  Node* stack = NewNode(jsgraph()->machine()->LoadStackPointer());
-  Node* tag = NewNode(jsgraph()->machine()->UintLessThan(), limit, stack);
-  stack_check.If(tag, BranchHint::kTrue);
-  stack_check.Then();
-  stack_check.Else();
-  Node* guard = NewNode(javascript()->CallRuntime(Runtime::kStackGuard, 0));
-  stack_check.End();
-  return guard;
-}
-
-
 bool AstGraphBuilder::CheckOsrEntry(IterationStatement* stmt) {
   if (info()->osr_ast_id() == stmt->OsrEntryId()) {
     info()->set_osr_expr_stack_height(std::max(