test: refactor, decouple HasReason from test framework machinery

Avoid providing the entire unit test framework dependency to tests that only
require access to the HasReason utility class.

E.g. reverselock_tests.cpp, sync_tests.cpp, util_check_tests.cpp, util_string_tests.cpp,
and script_parse_tests.cpp only require access to HasReason and nothing else.

src/test/sock_tests.cpp

@@ -4,6 +4,7 @@
 
 #include <common/system.h>
 #include <compat/compat.h>
+#include <test/util/common.h>
 #include <test/util/setup_common.h>
 #include <util/sock.h>
 #include <util/threadinterrupt.h>