Don't use Isolate::Current for AST debugging.

src/ast/ast.cc

Index: src/ast/ast.cc
diff --git a/src/ast/ast.cc b/src/ast/ast.cc
index 9b2c6388c1626c4bbe975dde7a01794acfc716e4..003e44e28487980436db3ed1a6d26fa2d4d60ecc 100644
--- a/src/ast/ast.cc
+++ b/src/ast/ast.cc
@@ -36,17 +36,11 @@ AST_NODE_LIST(DECL_ACCEPT)
 
 #ifdef DEBUG
 
-void AstNode::Print() { Print(Isolate::Current()); }
-
-
 void AstNode::Print(Isolate* isolate) {
   AstPrinter::PrintOut(isolate, this);
 }
 
 
-void AstNode::PrettyPrint() { PrettyPrint(Isolate::Current()); }
-
-
 void AstNode::PrettyPrint(Isolate* isolate) {
   PrettyPrinter::PrintOut(isolate, this);
 }