Fix presubmit error (multiple statements on the same line).

src/ast.h

Index: src/ast.h
diff --git a/src/ast.h b/src/ast.h
index 53ce1ab772ca97e447aad34dc5db037f437e2b16..d153f98a6ad91678d3f01dd756ac625b5917d3a5 100644
--- a/src/ast.h
+++ b/src/ast.h
@@ -154,7 +154,10 @@ class AstNode: public ZoneObject {
 
   // True if the AST node is critical (its execution is needed or externally
   // visible in some way).
-  virtual bool IsCritical() { UNREACHABLE(); return true; }
+  virtual bool IsCritical() {
+    UNREACHABLE();
+    return true;
+  }
 
   int num() { return num_; }
   void set_num(int n) { num_ = n; }