Slightly improved register assignment for %_IsObject on IA32 and ARM.

src/arm/lithium-arm.h

Index: src/arm/lithium-arm.h
===================================================================
--- src/arm/lithium-arm.h	(revision 8444)
+++ src/arm/lithium-arm.h	(working copy)
@@ -705,7 +705,7 @@
 };
 
 
-class LIsObject: public LTemplateInstruction<1, 1, 1> {
+class LIsObject: public LTemplateInstruction<1, 1, 0> {
  public:
   explicit LIsObject(LOperand* value) {
     inputs_[0] = value;
@@ -715,7 +715,7 @@
 };
 
 
-class LIsObjectAndBranch: public LControlInstruction<1, 2> {
+class LIsObjectAndBranch: public LControlInstruction<1, 1> {
  public:
   LIsObjectAndBranch(LOperand* value, LOperand* temp) {
     inputs_[0] = value;