Fix clippy::explicit_auto_deref warning

[taiki-e]

warning: deref which would be done by auto-deref
    --> crossbeam-epoch/src/atomic.rs:1715:43
     |
1715 |         let arr: &[MaybeUninit<usize>] = &*owned;
     |                                           ^^^^^^ help: try this: `owned`
     |
     = note: `#[warn(clippy::explicit_auto_deref)]` on by default
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref

warning: deref which would be done by auto-deref
    --> crossbeam-skiplist/src/base.rs:1045:21
     |
1045 |                     (*n).refs_and_height
     |                     ^^^^ help: try this: `n`
     |
     = note: `#[warn(clippy::explicit_auto_deref)]` on by default
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#explicit_auto_deref

[taiki-e]

bors r+

[bors]

Build succeeded:

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