clang-format: Set Bitcoin Core IncludeCategories

Replace the default llvm include categories with the ones specific to
Bitcoin Core.

src/test/blockchain_tests.cpp

@@ -2,8 +2,6 @@
 // Distributed under the MIT software license, see the accompanying
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
-#include <boost/test/unit_test.hpp>
-
 #include <chain.h>
 #include <node/blockstorage.h>
 #include <rpc/blockchain.h>
@@ -11,6 +9,8 @@
 #include <test/util/setup_common.h>
 #include <util/string.h>
 
+#include <boost/test/unit_test.hpp>
+
 #include <cstdlib>
 
 using util::ToString;