In the current implementation, WT_ERR_MSG jumps to the err label unconditionally, even if ret is 0. Similarly, WT_RET_MSG returns unconditionally, even if the return value is 0.

This behavior is rather surprising and inconsistent with the current semantics of WT_ERR and WT_RET. We should make the semantics consistent. Ideally, we could just take WT_ERR_MSG_CHK and just let that be the semantics for WT_ERR_MSG.

For the few cases that depend on macros such as WT_RET_MSG to return unconditionally, we could introduce a new macro, such as WT_RET_MSG_ALWAYS.