Reinitialize state in between individual unit tests.

This changes the TestingSetup fixture to be per-unit-test rather than global.
Most tests don't need it, so it's only invoked in a few.

src/test/rpc_wallet_tests.cpp

@@ -8,6 +8,8 @@
 #include "base58.h"
 #include "wallet.h"
 
+#include "test/test_bitcoin.h"
+
 #include <boost/algorithm/string.hpp>
 #include <boost/test/unit_test.hpp>
 
@@ -19,7 +21,7 @@ extern Value CallRPC(string args);
 
 extern CWallet* pwalletMain;
 
-BOOST_AUTO_TEST_SUITE(rpc_wallet_tests)
+BOOST_FIXTURE_TEST_SUITE(rpc_wallet_tests, TestingSetup)
 
 BOOST_AUTO_TEST_CASE(rpc_addmultisig)
 {