TODO: Add this commit description to the first commit

Currently `QueryVTable::value_from_cycle_error` field of a function pointer type uses the `FromCycleError` trait to call special code handling query cycles and constructing an erroneous query output value.
This trick however relies too heavily on trait impl specialization and makes those impls inconsistent (which is bad AFAIK).
Instead we can directly modify query vtables' `value_from_cycle_error` function pointer upon vtable initialization and get rid of `FromCycleError` as done in this PR.
Removal of `FromCycleError` might also be a desired change for some developers involved in the query system development due to some other reasons.

Author: zetanumbers