fix: speed up assert default details case

[erights]

Pick the lowest hanging performance fruit.

In general we try to avoid the

assert(cond, X`...`);

style, and use instead

cond || Fail`...`;

However, sometimes we are confident enough that the failure can never happen that we do not bother with the details (the

Something`...`

part). This happens often when we're just doing the assertion to inform the type checker of something we believe to be true. For these cases, we often write

assert(cond);

Yes, the success case is slower than the || Fail pattern by a function call. But the success case should not be more slower than that. It was, due to a completely unnecessary function call within the default argument for assert's optional second parameter.

Also fixed: The optional third parameter also happened to be doing work that was unneeded in the success case.