Improve exception message for aliased bundle fields (#2304)

- Shows groups of field names that share a common id (i.e. aliased)
- Show, as much as possible, them in the order that fields appear in bundle
- Updated BundleSpec's relevant tests

Co-authored-by: Megan Wachs <megan@sifive.com>
Co-authored-by: Jack Koenig <koenig@sifive.com>