[cond] auto_functionalize cond

[ydwu4]

Stack from ghstack (oldest at bottom):

• -> [cond] auto_functionalize cond #155645
• [refactor] simplify the implementation of check_input_alias_and_mutation_return_outputs #155749
• [cond] support gen_schema for cond #154193
• [cond] preserve merged phs meta for subgraph #155644

cc @voznesenskym @penguinwu @EikanWang @jgong5 @Guobing-Chen @XiaobingSuper @zhuhaozhe @blzheng @wenzhe-nrv @jiayisunx @ipiszy @chenyang78 @kadeng @muchulee8 @amjames @chauhang @aakhundov @coconutruben

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✅ You can merge normally! (1 Unrelated Failure)

As of commit 9cb2d5d with merge base 568ca89 ():

UNSTABLE - The following job is marked as unstable, possibly due to flakiness on trunk:

• pull / cuda12.8-py3.10-gcc9-sm75 / test (pr_time_benchmarks, 1, 1, linux.g4dn.metal.nvidia.gpu, unstable) (gh)
  MISSING REGRESSION TEST

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