Don't dispatch transformers to 'fantasy-land/reduce'

[wojpawlik]

_reduce no longer tries to dispatch transformers to fantasy-land/reduce, because reduced support is forbidden by the spec:

iii. f must return a value of the same type as x.
iv. No parts of f's return value should be checked.

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Extracted from #2762, discussing it over there could be messy.

This solution avoids unnecessary _xwrap. An alternative solution avoids nesting.

[CrossEye]

🌿

I can't see a reason not to do this, and it's certainly a simpler fix than the alternative. Any other thoughts, @ramda/core ?