Remove default monomorphic check code from functions and stubs that do not need it.

runtime/vm/assembler_dbc.h

 // Copyright (c) 2016, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #ifndef RUNTIME_VM_ASSEMBLER_DBC_H_
 #define RUNTIME_VM_ASSEMBLER_DBC_H_
 
 #ifndef RUNTIME_VM_ASSEMBLER_H_
 #error Do not include assembler_dbc.h directly; use assembler.h instead.
 #endif
@@ skipping 68 matching lines @@
   }
 
   ~Assembler() { }
 
   void Bind(Label* label);
   void Jump(Label* label);
 
   // Misc. functionality
   intptr_t CodeSize() const { return buffer_.Size(); }
   intptr_t prologue_offset() const { return 0; }
+  bool has_single_entry_point() const { return true; }
 
   // Count the fixups that produce a pointer offset, without processing
   // the fixups.
   intptr_t CountPointerOffsets() const { return 0; }
 
   const ZoneGrowableArray<intptr_t>& GetPointerOffsets() const {
     ASSERT(buffer_.pointer_offsets().length() == 0);  // No pointers in code.
     return buffer_.pointer_offsets();
   }
 
@@ skipping 91 matching lines @@
   GrowableArray<CodeComment*> comments_;
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_ASSEMBLER_DBC_H_