Do not suppress C4018 'expression' : signed/unsigned mismatch

The code compiles cleanly for the most part. Fix db_test.
  Move debug file to testutil library.

CMakeLists.txt

@@ -58,7 +58,7 @@ add_custom_command(OUTPUT ${BUILD_VERSION_CC}
 add_custom_target(GenerateBuildVersion DEPENDS ${BUILD_VERSION_CC})
 
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /Zi /nologo  /EHsc /GS /Gd /GR /GF /fp:precise /Zc:wchar_t /Zc:forScope /errorReport:queue")
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4018 /wd4100 /wd4101 /wd4127 /wd4189 /wd4200 /wd4244 /wd4267 /wd4296 /wd4305 /wd4307 /wd4309 /wd4512 /wd4701 /wd4702 /wd4800 /wd4804 /wd4996")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /FC /d2Zi+ /W3 /WX /wd4100 /wd4101 /wd4127 /wd4189 /wd4200 /wd4244 /wd4267 /wd4296 /wd4305 /wd4307 /wd4309 /wd4512 /wd4701 /wd4702 /wd4800 /wd4804 /wd4996")
 
 # Used to run CI build and tests so we can run faster
 set(OPTIMIZE_DEBUG_DEFAULT 0)        # Debug build is unoptimized by default use -DOPTDBG=1 to optimize
@@ -230,7 +230,6 @@ set(SOURCES
         util/thread_local.cc
         util/thread_status_impl.cc
         util/thread_status_updater.cc
-        util/thread_status_updater_debug.cc
         util/thread_status_util.cc
         util/thread_status_util_debug.cc
         util/vectorrep.cc
@@ -268,6 +267,7 @@ set(SOURCES
 # and linked to tests. Add test only code that is not #ifdefed for Release here.
 set(TESTUTIL_SOURCE
     db/db_test_util.cc
+    util/thread_status_updater_debug.cc
 )
 
 add_library(rocksdblib${ARTIFACT_SUFFIX} ${SOURCES})

db/db_test.cc

@@ -788,10 +788,10 @@ TEST_F(DBTest, GetUserDefinedTableProperties) {
   }
   ASSERT_EQ(10u + 11u + 12u + 13u, sum);
 
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
   collector_factory->num_created_ = 0;
   dbfull()->TEST_CompactRange(0, nullptr, nullptr);
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 }
 #endif  // ROCKSDB_LITE
 
@@ -811,7 +811,7 @@ TEST_F(DBTest, UserDefinedTablePropertiesContext) {
     }
     Flush(1);
   }
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 
   collector_factory->num_created_ = 0;
   // Trigger automatic compactions.
@@ -822,11 +822,11 @@ TEST_F(DBTest, UserDefinedTablePropertiesContext) {
     Flush(1);
     dbfull()->TEST_WaitForCompact();
   }
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 
   collector_factory->num_created_ = 0;
   dbfull()->TEST_CompactRange(0, nullptr, nullptr, handles_[1]);
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 
   // Come back to write to default column family
   collector_factory->num_created_ = 0;
@@ -838,7 +838,7 @@ TEST_F(DBTest, UserDefinedTablePropertiesContext) {
     }
     Flush();
   }
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 
   collector_factory->num_created_ = 0;
   // Trigger automatic compactions.
@@ -849,11 +849,11 @@ TEST_F(DBTest, UserDefinedTablePropertiesContext) {
     Flush();
     dbfull()->TEST_WaitForCompact();
   }
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 
   collector_factory->num_created_ = 0;
   dbfull()->TEST_CompactRange(0, nullptr, nullptr);
-  ASSERT_GT(collector_factory->num_created_, 0);
+  ASSERT_GT(collector_factory->num_created_, 0U);
 }
 
 #ifndef ROCKSDB_LITE
@@ -5140,7 +5140,7 @@ class RecoveryTestHelper {
   // Overwrite data with 'a' from offset for length len
   static void InduceCorruption(const std::string& filename, uint32_t offset,
                                uint32_t len) {
-    ASSERT_GT(len, 0);
+    ASSERT_GT(len, 0U);
 
     int fd = open(filename.c_str(), O_RDWR);