Add required locks in tests

Unit tests with DEBUG_LOCKORDER were running into assertions.

src/test/transaction_tests.cpp

@@ -254,6 +254,7 @@ BOOST_AUTO_TEST_CASE(test_Get)
 
 BOOST_AUTO_TEST_CASE(test_IsStandard)
 {
+    LOCK(cs_main);
     CBasicKeyStore keystore;
     CCoinsView coinsDummy;
     CCoinsViewCache coins(coinsDummy);