[refactoring] update ast structure of "Nop" node

pkg/ast/node.go

@@ -597,6 +597,7 @@ func (n *StmtNamespace) Accept(v NodeVisitor) {
 // StmtNop node
 type StmtNop struct {
 	Node
+	SemiColonTkn *token.Token
 }
 
 func (n *StmtNop) Accept(v NodeVisitor) {

pkg/ast/visitor/filter_tokens.go

@@ -235,3 +235,7 @@ func (v *FilterTokens) StmtDeclare(n *ast.StmtDeclare) {
 	n.EndDeclareTkn = nil
 	n.SemiColonTkn = nil
 }
+
+func (v *FilterTokens) StmtNop(n *ast.StmtNop) {
+	n.SemiColonTkn = nil
+}

pkg/printer/printer.go

@@ -2581,13 +2581,8 @@ func (p *Printer) printStmtNamespace(n *ast.StmtNamespace) {
 	p.printToken(n.SemiColonTkn, ";")
 }
 
-func (p *Printer) printStmtNop(n ast.Vertex) {
-	p.printFreeFloatingOrDefault(n, token.Start, p.bufStart)
-	p.printFreeFloating(n, token.SemiColon)
-	if n.GetNode().Tokens.IsEmpty() {
-		p.write([]byte(";"))
-	}
-	p.printFreeFloating(n, token.End)
+func (p *Printer) printStmtNop(n *ast.StmtNop) {
+	p.printToken(n.SemiColonTkn, ";")
 }
 
 func (p *Printer) printStmtPropertyList(n ast.Vertex) {