Improvements to inequality solving

fixes #8206 (please feel free to any others that are related that also work with these changes)
fixes #8518
I'm sorry, I'm not able to piece together the intention of your question. What is it that you are concerned about? What would you like to see changed? The only thing I can think is that you are looking for a call to `reduce_rational_inequalities` but that's where `reduce_inequalities` sends the expression to.