test: move and simplify BOOST_CHECK ostream helpers

Move the operator<< overloads used by BOOST_CHECK_* out of the
unit test machinery test/setup_common, into test/util/common.h.

And replace the individual per-type ToString() overloads with
a single concept-constrained template that covers any type
exposing a ToString() method. This is important to not add
uint256.h and transaction_identifier.h dependencies to the
shared test/util/common.h file.

Co-authored-by: furszy <matiasfurszyfer@protonmail.com>

src/wallet/test/coinselector_tests.cpp

@@ -7,6 +7,7 @@
 #include <policy/policy.h>
 #include <primitives/transaction.h>
 #include <random.h>
+#include <test/util/common.h>
 #include <test/util/setup_common.h>
 #include <util/translation.h>
 #include <wallet/coincontrol.h>

src/wallet/test/db_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <boost/test/unit_test.hpp>
 
+#include <test/util/common.h>
 #include <test/util/setup_common.h>
 #include <util/check.h>
 #include <util/fs.h>
@@ -14,7 +15,6 @@
 #include <wallet/walletutil.h>
 
 #include <cstddef>
-#include <fstream>
 #include <memory>
 #include <span>
 #include <string>

src/wallet/test/wallet_tests.cpp

@@ -17,6 +17,7 @@
 #include <policy/policy.h>
 #include <rpc/server.h>
 #include <script/solver.h>
+#include <test/util/common.h>
 #include <test/util/logging.h>
 #include <test/util/random.h>
 #include <test/util/setup_common.h>

src/wallet/test/wallet_transaction_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <wallet/transaction.h>
 
+#include <test/util/common.h>
 #include <wallet/test/wallet_test_fixture.h>
 
 #include <boost/test/unit_test.hpp>

src/wallet/test/walletload_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <wallet/test/util.h>
 #include <wallet/wallet.h>
+#include <test/util/common.h>
 #include <test/util/logging.h>
 #include <test/util/setup_common.h>