make classify_drop_access_kind iterate

[SparrowLii]

This PR:

1. fixes the FIXME of classify_drop_access_kind func in the borrowck part. The process of obtaining StorageDeadOrDrop has been changed from recursive to iterative.
2. gets place_ty in each iteration, avoid repeatedly getting the ty of the same place (O(n^2) => O(n))

[rust-highfive]

r? @oli-obk

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[oli-obk]

@bors try @rust-timer queue

I don't expect perf changes, but let's make sure before rolling up

[rust-timer]

Awaiting bors try build completion.

@rustbot label: +S-waiting-on-perf

[bors]

⌛ Trying commit a34e1b5 with merge 7f71280f22cfccea406a5595cb1f3504279a0fd1...

[bors]

☀️ Try build successful - checks-actions
Build commit: 7f71280f22cfccea406a5595cb1f3504279a0fd1 (7f71280f22cfccea406a5595cb1f3504279a0fd1)

[rust-timer]

Queued 7f71280f22cfccea406a5595cb1f3504279a0fd1 with parent b21759f, future comparison URL.

[rust-timer]

Finished benchmarking commit (7f71280f22cfccea406a5595cb1f3504279a0fd1): comparison url.

Summary: This benchmark run did not return any relevant results.

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.

[oli-obk]

@bors r+ rollup

Excellent! Thanks for cleaning that up, I totally forgot we added it until your PR removed it

[bors]

📌 Commit a34e1b5 has been approved by oli-obk

[bors]

⌛ Testing commit a34e1b5 with merge d8e59ed...

[bors]

☀️ Test successful - checks-actions
Approved by: oli-obk
Pushing d8e59ed to master...

[rust-timer]

Finished benchmarking commit (d8e59ed): comparison url.

Summary: This benchmark run did not return any relevant results.

If you disagree with this performance assessment, please file an issue in rust-lang/rustc-perf.