[turbofan] Fix more -Wsign-compare warnings.

test/unittests/eh-frame-iterator-unittest.cc

Index: test/unittests/eh-frame-iterator-unittest.cc
diff --git a/test/unittests/eh-frame-iterator-unittest.cc b/test/unittests/eh-frame-iterator-unittest.cc
index 27485db67eb8d6d3263e02d4a9d59a302876bdfc..1b8adddaee3b3ecbc684c25349bc0c081df122dc 100644
--- a/test/unittests/eh-frame-iterator-unittest.cc
+++ b/test/unittests/eh-frame-iterator-unittest.cc
@@ -40,7 +40,7 @@ TEST_F(EhFrameIteratorTest, Skip) {
 TEST_F(EhFrameIteratorTest, ULEB128Decoding) {
   static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
   EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
-  EXPECT_EQ(624485, iterator.GetNextULeb128());
+  EXPECT_EQ(624485u, iterator.GetNextULeb128());
   EXPECT_TRUE(iterator.Done());
 }