Updates to asserts for formal regression

Created by: silabs-mateilga

Some fixes triggered by cleaning up formal regression:

• Updates to debug_asserts to start using common support logic for exception triggers
• Fixed csr helper functions in rvfi_instr_if to match spec definition, added csr_write_intended, which gives a intended value for the update of a csr
• cleaned up and expanded scope for a_rlblifts_lockedexec in pmprvfi_asserts