Revert "Mark attributes consumed by check_mod_attrs as normal"

[tmiasko]

This reverts commit d78b22f.

Those changes were incompatible with incremental compilation since the
effect check_mod_attrs has with respect to marking the attributes as
used is neither persisted nor recomputed.

[rust-highfive]

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[tmiasko]

Reproducer using another attribute:

$ cat src/main.rs
#![feature(marker_trait_attr)]

#[marker]
trait A {}

fn main() {}
$ cargo check
    Checking unused v0.1.0 (/../unused)
    Finished dev [unoptimized + debuginfo] target(s) in 0.43s
$ touch src/main.rs
$ cargo check
    Checking unused v0.1.0 (/../unused)
warning: unused attribute
 --> src/main.rs:3:1
  |
3 | #[marker]
  | ^^^^^^^^^
  |
  = note: `#[warn(unused_attributes)]` on by default

    Finished dev [unoptimized + debuginfo] target(s) in 0.25s

Looks like the general incompatibility of unused attributes lint
with incremental compilation is a known issue: #58633, #65023.

r? @petrochenkov

[petrochenkov]

@bors r+

[bors]

📌 Commit 34f8394 has been approved by petrochenkov

[nnethercote]

@bors p=1

Because it fixes a perf regression.

[bors]

⌛ Testing commit 34f8394 with merge fbc46b7...

[bors]

☀️ Test successful - checks-azure
Approved by: petrochenkov
Pushing fbc46b7 to master...