test: Remove useless test_bitcoin_main.cpp

src/test/main.cpp

@@ -0,0 +1,7 @@
+// Copyright (c) 2011-2019 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#define BOOST_TEST_MODULE Bitcoin Core Test Suite
+
+#include <boost/test/unit_test.hpp>