[turbofan] Remove obsolete --turbo-shipping flag.

src/ast/ast-numbering.cc

Index: src/ast/ast-numbering.cc
diff --git a/src/ast/ast-numbering.cc b/src/ast/ast-numbering.cc
index 1be5940adc38654356e1e61bdec91dedf0ef7a36..5fea93331243a9e62808c549fec0d34344c1d9a0 100644
--- a/src/ast/ast-numbering.cc
+++ b/src/ast/ast-numbering.cc
@@ -56,12 +56,7 @@ class AstNumberingVisitor final : public AstVisitor<AstNumberingVisitor> {
     DisableSelfOptimization();
   }
   void DisableCrankshaft(BailoutReason reason) {
-    if (FLAG_turbo_shipping) {
-      properties_.flags() |= AstProperties::kDontCrankshaft;
-    } else {
-      dont_optimize_reason_ = reason;
-      DisableSelfOptimization();
-    }
+    properties_.flags() |= AstProperties::kDontCrankshaft;
   }
 
   template <typename Node>