Make Range#reverse_each to raise an exception if endless

[kyanagi]

https://bugs.ruby-lang.org/issues/18551

Currently, Range#reverse_each for an endless range never returns.

% ruby -e '(1..).reverse_each { }'
# never return ...

(This is because Enumerable#reverse_each tries #to_a and #to_a for an endless range comes into an infinite loop.)

I think Range#reverse_each for an endless range should raise an exception, similar to Range#each for a beginless range.

% ruby -e '(..1).each { }' 
-e:1:in `each': can't iterate from NilClass (TypeError)
	from -e:1:in `<main>'