Revert "Fully support pairs in the register allocator."

Libcore tests fail.

This reverts commit 41aedbb684ccef76ff8373f39aba606ce4cb3194.

Change-Id: I2572f120d4bbaeb7a4d4cbfd47ab00c9ea39ac6c
diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index 800af40..ade3138 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -646,7 +646,7 @@
     if (GetResultType() == Primitive::kPrimLong) {
       return new(GetBlock()->GetGraph()->GetArena()) HLongConstant(value);
     } else {
-      DCHECK_EQ(GetResultType(), Primitive::kPrimInt);
+      DCHECK(GetResultType() == Primitive::kPrimInt);
       return new(GetBlock()->GetGraph()->GetArena()) HIntConstant(value);
     }
   }