Fix -Wsign-compare errors in TF tests under GCC 4.9.2

test/unittests/compiler/graph-reducer-unittest.cc

Index: test/unittests/compiler/graph-reducer-unittest.cc
diff --git a/test/unittests/compiler/graph-reducer-unittest.cc b/test/unittests/compiler/graph-reducer-unittest.cc
index 8b95872a7b006b2e5525718e5a7e1818715141c1..2d54e21442d36c6c56d3f4bb4912d0eb8e1fe0be 100644
--- a/test/unittests/compiler/graph-reducer-unittest.cc
+++ b/test/unittests/compiler/graph-reducer-unittest.cc
@@ -596,12 +596,12 @@ TEST_F(GraphReducerTest, ReduceNew1) {
 TEST_F(GraphReducerTest, Wrapping1) {
   Node* end = graph()->NewNode(&kOpA0);
   graph()->SetEnd(end);
-  EXPECT_EQ(1, graph()->NodeCount());
+  EXPECT_EQ(1U, graph()->NodeCount());
 
   A0Wrapper r(graph());
 
   ReduceGraph(&r);
-  EXPECT_EQ(2, graph()->NodeCount());
+  EXPECT_EQ(2U, graph()->NodeCount());
 
   Node* nend = graph()->end();
   EXPECT_NE(end, nend);
@@ -614,12 +614,12 @@ TEST_F(GraphReducerTest, Wrapping1) {
 TEST_F(GraphReducerTest, Wrapping2) {
   Node* end = graph()->NewNode(&kOpB0);
   graph()->SetEnd(end);
-  EXPECT_EQ(1, graph()->NodeCount());
+  EXPECT_EQ(1U, graph()->NodeCount());
 
   B0Wrapper r(graph());
 
   ReduceGraph(&r);
-  EXPECT_EQ(3, graph()->NodeCount());
+  EXPECT_EQ(3U, graph()->NodeCount());
 
   Node* nend = graph()->end();
   EXPECT_NE(end, nend);