Minor DCHECK bug fix.

Rationale:
Should use the utility to test for SIMD result,
not a hard is vector test.

Test: 623 is regression test for DCHECK fail
Change-Id: I1d7949fa25139f8a3734986d5de7989ed32ff2bd
diff --git a/compiler/optimizing/nodes_vector.h b/compiler/optimizing/nodes_vector.h
index 523bca8..9b114eb 100644
--- a/compiler/optimizing/nodes_vector.h
+++ b/compiler/optimizing/nodes_vector.h
@@ -325,7 +325,7 @@
                       uint32_t dex_pc)
       : HVecUnaryOperation(
             kVecReplicateScalar, allocator, scalar, packed_type, vector_length, dex_pc) {
-    DCHECK(!scalar->IsVecOperation());
+    DCHECK(!ReturnsSIMDValue(scalar));
   }
 
   // A replicate needs to stay in place, since SIMD registers are not