Mark TypeFinalizing/Unfinalizing as requiring closed world (#8039)

They change the ABI, possibly making casts start to work/fail.

Author: kripken

scripts/fuzz_opt.py

@@ -2484,6 +2484,8 @@ def write_commands(commands, filename):
                          ("--abstract-type-refining",),
                          ("--cfp",),
                          ("--cfp-reftest",),
+                         ("--type-finalizing",),
+                         ("--type-unfinalizing",),
                          ("--type-ssa",),
                          ("--type-merging",),
                          ("--unsubtyping",)}