VM: Use read-only handle Object::dynamic_type() where possible.

runtime/vm/flow_graph_compiler_mips.cc

 // Copyright (c) 2013, 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.
 
 #include "vm/globals.h"  // Needed here to get TARGET_ARCH_MIPS.
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/ast_printer.h"
@@ skipping 431 matching lines @@
     __ lw(A1, Address(SP, 0));  // Get instantiator type arguments.
     // A1: instantiator type arguments.
     // Check if type arguments are null, i.e. equivalent to vector of dynamic.
     __ LoadObject(T7, Object::null_object());
     __ beq(A1, T7, is_instance_lbl);
     __ lw(T2,
         FieldAddress(A1, TypeArguments::type_at_offset(type_param.index())));
     // R2: concrete type of type.
     // Check if type argument is dynamic.
     __ BranchEqual(T2,
-        Type::ZoneHandle(zone(), Type::DynamicType()), is_instance_lbl);
+        Object::dynamic_type(), is_instance_lbl);
     __ BranchEqual(T2,
         Type::ZoneHandle(zone(), Type::ObjectType()), is_instance_lbl);
 
     // For Smi check quickly against int and num interfaces.
     Label not_smi;
     __ andi(CMPRES1, A0, Immediate(kSmiTagMask));
     __ bne(CMPRES1, ZR, &not_smi);  // Value is Smi?
     __ BranchEqual(T2,
         Type::ZoneHandle(zone(), Type::IntType()), is_instance_lbl);
     __ BranchEqual(T2,
@@ skipping 1416 matching lines @@
   __ AddImmediate(SP, kDoubleSize);
 }
 
 
 #undef __
 
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS