IsReferenceTypes() now uses IsNonZeroReferenceTypes() and IsZero().

Removes duplicate code.

Change-Id: Ib757fabf70c7e6eaa2ceda9bd9ca889192cdb4cf
diff --git a/src/verifier/reg_type.h b/src/verifier/reg_type.h
index a2fb306..6f0193f 100644
--- a/src/verifier/reg_type.h
+++ b/src/verifier/reg_type.h
@@ -144,9 +144,7 @@
   }
 
   bool IsReferenceTypes() const {
-    return IsReference() || IsUnresolvedReference() || IsZero() ||
-        IsUninitializedReference() || IsUninitializedThisReference() ||
-        IsUnresolvedAndUninitializedReference() || IsUnresolvedAndUninitializedThisReference();
+    return IsNonZeroReferenceTypes() || IsZero();
   }
   bool IsNonZeroReferenceTypes() const {
     return IsReference() || IsUnresolvedReference() ||