Update Integer32ToSmiField, SmiToInteger32, and SmiComprare to support 31-bit SMI for x32 port

src/x64/assembler-x64.h

Index: src/x64/assembler-x64.h
diff --git a/src/x64/assembler-x64.h b/src/x64/assembler-x64.h
index 92d63d2e7ccfdde1c34d295e321ce3323aa67f03..9009e4ff59dcbe5a7b9584212ed6d71493014d9c 100644
--- a/src/x64/assembler-x64.h
+++ b/src/x64/assembler-x64.h
@@ -357,6 +357,10 @@ inline Condition ReverseCondition(Condition cc) {
 class Immediate BASE_EMBEDDED {
  public:
   explicit Immediate(int32_t value) : value_(value) {}
+  explicit Immediate(Smi* value) {
+    ASSERT(SmiValuesAre31Bits());  // Only available for 31-bit SMI.
+    value_ = static_cast<int32_t>(reinterpret_cast<intptr_t>(value));
+  }
 
  private:
   int32_t value_;