ARM & MIPS: Try to use the object pool before trying to embed a pointer, like ARM64 and X64.

runtime/vm/assembler_mips.h

 // 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.
 
 #ifndef VM_ASSEMBLER_MIPS_H_
 #define VM_ASSEMBLER_MIPS_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_mips.h directly; use assembler.h instead.
 #endif
@@ skipping 1500 matching lines @@
   void GetNextPC(Register dest, Register temp = kNoRegister);
 
   void ReserveAlignedFrameSpace(intptr_t frame_space);
 
   // Create a frame for calling into runtime that preserves all volatile
   // registers.  Frame's SP is guaranteed to be correctly aligned and
   // frame_space bytes are reserved under it.
   void EnterCallRuntimeFrame(intptr_t frame_space);
   void LeaveCallRuntimeFrame();
 
+  bool CanLoadFromObjectPool(const Object& object) const;
   void LoadWordFromPoolOffset(Register rd, int32_t offset);
   void LoadObject(Register rd, const Object& object);
   void LoadUniqueObject(Register rd, const Object& object);
   void LoadExternalLabel(Register rd,
                          const ExternalLabel* label,
                          Patchability patchable);
   void LoadNativeEntry(Register rd,
                        const ExternalLabel* label,
                        Patchability patchable);
   void PushObject(const Object& object);
@@ skipping 208 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_MIPS_H_