It would be nice if there was a way to tell compilers not to drop the lock stack and thus issue warnings when accessing a symbol that needs a lock inside `Assume`/`Assert`.

Hit by (at least): @ajtowns , @jnewbery , me.
#ifndef BITCOIN_UTIL_CHECK_H
#define BITCOIN_UTIL_CHECK_H
#if defined(HAVE_CONFIG_H)
#include <config/bitcoin-config.h>
#endif
#include <tinyformat.h>
#include <stdexcept>
class NonFatalCheckError : public std::runtime_error