General pipeline optimizations

[dekmm]

If at least one of the following conditions are true:

• the stream is unordered (e.g. the Stream::unordered has been called)
• the terminal operation does not require the order to be preserved (for example forEach and min)
• the stream is parallel and terminal operation does not require the order to be preserved for parallel streams

Then, the longest consecutive string of intermediate operations starting from the back that only affects the order of elements (i.e. Sorted) can be removed.

[dekmm]

It is possible to reorder intermediate operations that are of different types while still preserving Stream equivalence.

Original operation	Operations that can be moved before/after the original operation
filter	sorted, distinct
sorted	filter, distinct
distinct	filter, sorted

[julgus]

Closing this issue as it seems like this was already implemented in RemoveOrderAffectingOperations.