make #[track_caller] actually do stuff in Steal::borrow

[BoxyUwU]

makes this ICE message useful:
thread 'rustc' panicked at 'attempted to read from stolen value', /rustc/ac2d9fc509e36d1b32513744adf58c34bcc4f43c\compiler\rustc_data_structures\src\steal.rs:37:21

[rust-highfive]

r? @nagisa

(rust-highfive has picked a reviewer for you, use r? to override)

[eddyb]

This might be sensitive for incremental:

@bors try @rust-timer queue

[rust-timer]

Awaiting bors try build completion.

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

[bors]

⌛ Trying commit f1e71a5 with merge 26605d2c2c54440efef2a4936728fe5404196afa...

[eddyb]

r=me if perf comes out neutral

[bors]

☀️ Try build successful - checks-actions
Build commit: 26605d2c2c54440efef2a4936728fe5404196afa (26605d2c2c54440efef2a4936728fe5404196afa)

[rust-timer]

Queued 26605d2c2c54440efef2a4936728fe5404196afa with parent 7342213, future comparison URL.

[rust-timer]

Finished benchmarking commit (26605d2c2c54440efef2a4936728fe5404196afa): comparison url.

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

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

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR led to changes in compiler perf.

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

[workingjubilee]

@bors r=eddyb

[bors]

📌 Commit f1e71a5 has been approved by eddyb

[klensy]

Better add test to track error message :-)

[bors]

⌛ Testing commit f1e71a5 with merge 218a96c...

[bors]

☀️ Test successful - checks-actions
Approved by: eddyb
Pushing 218a96c to master...

[rust-timer]

Finished benchmarking commit (218a96c): comparison url.

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

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

@rustbot label: -perf-regression