Low-level functions only include stack trace in test builds while higher-level functions ship with stack trace built-in. Stack traces include all parameters passed to the function but production builds only create the parameter list when the log level is set high enough, i.e. debug or trace depending on the function.
* Replace remaining NDEBUG blocks with the more granular DEBUG_UNIT.
* Remove some debug memset() calls in MemContext since valgrind is more useful for these checks.