Fix gcc 4.9.2 signed-compare error.

test/cctest/compiler/test-run-machops.cc

Index: test/cctest/compiler/test-run-machops.cc
diff --git a/test/cctest/compiler/test-run-machops.cc b/test/cctest/compiler/test-run-machops.cc
index 255c96e21967ffa19bd8ace8c421ebe3225575b1..08f8f3f4c31da4fb474c7dc3fb056af7c0cfaa53 100644
--- a/test/cctest/compiler/test-run-machops.cc
+++ b/test/cctest/compiler/test-run-machops.cc
@@ -5459,7 +5459,7 @@ TEST(RunRoundUint64ToFloat64) {
   BufferedRawMachineAssemblerTester<double> m(kMachUint64);
   m.Return(m.RoundUint64ToFloat64(m.Parameter(0)));
 
-  for (int i = 0; i < arraysize(values); i++) {
+  for (size_t i = 0; i < arraysize(values); i++) {
     CHECK_EQ(bit_cast<double>(values[i].expected), m.Call(values[i].input));
   }
 }
@@ -5549,7 +5549,7 @@ TEST(RunRoundUint64ToFloat32) {
   BufferedRawMachineAssemblerTester<float> m(kMachUint64);
   m.Return(m.RoundUint64ToFloat32(m.Parameter(0)));
 
-  for (int i = 0; i < arraysize(values); i++) {
+  for (size_t i = 0; i < arraysize(values); i++) {
     CHECK_EQ(bit_cast<float>(values[i].expected), m.Call(values[i].input));
   }
 }