Always collect tokens when we are already inside a collect_tokens call

[Aaron1011]

Fixes #81007

This is needed to ensure that the LazyTokenStream we use does not
include attributes - the outer call may include the attributes, which we
don't want to include in the LazyTokenSTream.

[rust-highfive]

r? @oli-obk

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[bors]

☔ The latest upstream changes (presumably #80993) made this pull request unmergeable. Please resolve the merge conflicts.

[Aaron1011]

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

[bors]

⌛ Trying commit 372b567 with merge 9f6de25f295e73311e6356b40ebab59069798fce...

[bors]

☀️ Try build successful - checks-actions
Build commit: 9f6de25f295e73311e6356b40ebab59069798fce (9f6de25f295e73311e6356b40ebab59069798fce)

[rust-timer]

Queued 9f6de25f295e73311e6356b40ebab59069798fce with parent e48eb37, future comparison URL.

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

[rust-timer]

Finished benchmarking try commit (9f6de25f295e73311e6356b40ebab59069798fce): comparison url.

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. Please note that if the perf results are neutral, you should likely undo the rollup=never given below by specifying rollup- to bors.

Importantly, though, if the results of this run are non-neutral do not roll this PR up -- it will mask other regressions or improvements in the roll up.

@bors rollup=never
@rustbot label: +S-waiting-on-review -S-waiting-on-perf

[Aaron1011]

This is implemented (with some extra performance improvements) in #81017. Once that PR is merged, this PR can be merged with just the test.

[Aaron1011]

Closing in favor of #81177, which accomplishes the same result more efficiently.