builder: Comment out the copy_if_assignment's assignment part

As the comment says - because we don't need it and it's only
complicates our life.

But if it is used anywhere aside expressions - that will be a problem
slotworks: remove asserts to allow normal table elements be mass-assigned

It's not working anyway, so who cares...
unwarper: allow a break to end at an outer end rather then at the current end

Plus implement an infrastructure to unveil other such JMP->JMP = JMP
optimisations. Why I haven't made it before?..
unwrapper: Allow nested if-falses to end at an outer end
unwarper: solidify requirements for the logical expression

So it will be mistaken with an ordinary if a bit less often
unwarper: Reduce a complexity of the if statement expression-end search routines

As a bonus - now they are able to handle even more insane stuff.
Simplier means better! Sometimes.
unwarper: The most usefull commit ever: make a sarcastic comment
test: even more testcases extracted from still unprocessable X:R scripts