Make the runtime entry for setting/changing accessors "atomic".

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index 5559788b361e31d86e957951f080797282bc3ffc..e259fc460033025342f66e848d4643112b78837c 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -1500,11 +1500,15 @@ void FullCodeGenerator::VisitObjectLiteral(ObjectLiteral* expr) {
         __ lw(a0, MemOperand(sp));
         __ push(a0);
         VisitForStackValue(key);
-        __ li(a1, Operand(property->kind() == ObjectLiteral::Property::SETTER ?
-                           Smi::FromInt(1) :
-                           Smi::FromInt(0)));
-        __ push(a1);
-        VisitForStackValue(value);
+        if (property->kind() == ObjectLiteral::Property::GETTER) {
+          VisitForStackValue(value);
+          __ LoadRoot(a1, Heap::kNullValueRootIndex);
+          __ push(a1);
+        } else {
+          __ LoadRoot(a1, Heap::kNullValueRootIndex);
+          __ push(a1);
+          VisitForStackValue(value);
+        }
         __ li(a0, Operand(Smi::FromInt(NONE)));
         __ push(a0);
         __ CallRuntime(Runtime::kDefineOrRedefineAccessorProperty, 5);