split the isa support file
Created by: silabs-krdosvik
Added "a lot" of new commits to https://github.com/openhwgroup/core-v-verif/pull/2093 (but used rebase to not make a mess) and therefore also a new PR.
- splitted the isa_support file into several files.
- Fixed dummy assert as it used logic that was removed from the isa_support file (logic copied from uvma_rvfi_instr and made general)