[turbofan] Fix more -Wsign-compare warnings.

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

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/eh-frame.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 // Test enabled only on supported architectures.
 #if defined(V8_TARGET_ARCH_X64) || defined(V8_TARGET_ARCH_ARM) || \
     defined(V8_TARGET_ARCH_ARM64)
@@ skipping 22 matching lines @@
   iterator.Skip(2);
   EXPECT_EQ(2, iterator.GetCurrentOffset());
   EXPECT_EQ(0xc0, iterator.GetNextByte());
   iterator.Skip(1);
   EXPECT_TRUE(iterator.Done());
 }
 
 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());
 }
 
 TEST_F(EhFrameIteratorTest, SLEB128DecodingPositive) {
   static const byte kEncoded[] = {0xe5, 0x8e, 0x26};
   EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
   EXPECT_EQ(624485, iterator.GetNextSLeb128());
   EXPECT_TRUE(iterator.Done());
 }
 
 TEST_F(EhFrameIteratorTest, SLEB128DecodingNegative) {
   static const byte kEncoded[] = {0x9b, 0xf1, 0x59};
   EhFrameIterator iterator(&kEncoded[0], &kEncoded[0] + sizeof(kEncoded));
   EXPECT_EQ(-624485, iterator.GetNextSLeb128());
   EXPECT_TRUE(iterator.Done());
 }
 
 #endif