[chore](build) Use include-what-you-use to optimize includes (PART III) (#18958)

Currently, there are some useless includes in the codebase. We can use a tool named include-what-you-use to optimize these includes. By using a strict include-what-you-use policy, we can get lots of benefits from it.

be/test/util/string_util_test.cpp

@@ -17,9 +17,11 @@
 
 #include "util/string_util.h"
 
-#include <gtest/gtest.h>
+#include <gtest/gtest-message.h>
+#include <gtest/gtest-test-part.h>
+#include <stdint.h>
 
-#include "util/cpu_info.h"
+#include "gtest/gtest_pred_impl.h"
 
 namespace doris {