Enable snapshots on MIPS. This is based on

src/mips/regexp-macro-assembler-mips.cc

Index: src/mips/regexp-macro-assembler-mips.cc
===================================================================
--- src/mips/regexp-macro-assembler-mips.cc	(revision 11074)
+++ src/mips/regexp-macro-assembler-mips.cc	(working copy)
@@ -386,7 +386,7 @@
 
     // Restore regexp engine registers.
     __ MultiPop(regexp_registers_to_retain);
-    __ li(code_pointer(), Operand(masm_->CodeObject()));
+    __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE);
     __ lw(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
 
     // Check if function returned non-zero for success or zero for failure.
@@ -698,7 +698,7 @@
     // Initialize backtrack stack pointer.
     __ lw(backtrack_stackpointer(), MemOperand(frame_pointer(), kStackHighEnd));
     // Initialize code pointer register
-    __ li(code_pointer(), Operand(masm_->CodeObject()));
+    __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE);
     // Load previous char as initial value of current character register.
     Label at_start;
     __ lw(a0, MemOperand(frame_pointer(), kAtStart));
@@ -783,7 +783,7 @@
 
       // String might have moved: Reload end of string from frame.
       __ lw(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
-      __ li(code_pointer(), Operand(masm_->CodeObject()));
+      __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE);
       SafeReturn();
     }
 
@@ -813,7 +813,7 @@
       // Otherwise use return value as new stack pointer.
       __ mov(backtrack_stackpointer(), v0);
       // Restore saved registers and continue.
-      __ li(code_pointer(), Operand(masm_->CodeObject()));
+      __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE);
       __ lw(end_of_input_address(), MemOperand(frame_pointer(), kInputEnd));
       SafeReturn();
     }
@@ -1010,7 +1010,7 @@
   __ PrepareCallCFunction(num_arguments, scratch);
   __ mov(a2, frame_pointer());
   // Code* of self.
-  __ li(a1, Operand(masm_->CodeObject()));
+  __ li(a1, Operand(masm_->CodeObject()), CONSTANT_SIZE);
   // a0 becomes return address pointer.
   ExternalReference stack_guard_check =
       ExternalReference::re_check_stack_guard_state(masm_->isolate());
@@ -1229,7 +1229,7 @@
   if (OS::ActivationFrameAlignment() != 0) {
     __ lw(sp, MemOperand(sp, 16));
   }
-  __ li(code_pointer(), Operand(masm_->CodeObject()));
+  __ li(code_pointer(), Operand(masm_->CodeObject()), CONSTANT_SIZE);
 }