Rollup merge of #153216 - lqd:polonius-soundness-tests, r=Kivooeo

mark two polonius tests as known-bug

As described in rust-lang/rust#153215, we want to track these two tests in case anything changes and when/if other fixes land.

As discussed in this week's meeting, r? @jackh726 (or anyone)

Author: JonathanBrouwer