Update reported width from div/rem to match FIRRTL results (#1748) (#1770)

* Update reported width from div/rem to match FIRRTL results

* Add tests for width of % and / on UInt and SInt

* Add loop-based test for known UInt/SInt op result widths

Co-authored-by: Jack Koenig <koenig@sifive.com>
(cherry picked from commit 98ce9194

)

Co-authored-by: Albert Magyar <albert.magyar@gmail.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>