[rustdoc] Correctly handle should_panic doctest attribute and fix --no-run test flag on the 2024 edition

[GuillaumeGomez]

Fixes #143009.
Fixes #143858.

Supersedes #143900.

For --no-run, we forgot to check the "global" options in the 2024 edition, fixed in the first commit.

For should_panic fix, the exit code check has been fixed.

r? @fmease

[rustbot]

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[GuillaumeGomez]

Let's see if it works like that, otherwise I'll add some cfg(bootstrap) around. Locally with stage 2 it worked fine.

[GuillaumeGomez]

Ah right, forgot to fix std doc examples.

[GuillaumeGomez]

Checking all previously failing CIs.

@bors try jobs=armhf-gnu,test-various,x86_64-gnu-aux

[rust-bors]

💔 Test for 0c093af failed: CI. Failed jobs:

• try - test-various (web logs, extended logs)

[GuillaumeGomez]

So the error comes from the fact that should_panic is ignored on some platforms by libtest and rustdoc didn't do this check. I added it as well.

Let's try again.

@bors try jobs=armhf-gnu,test-various,x86_64-gnu-aux

[rust-bors]

💔 Test for 7103c01 failed: CI. Failed jobs:

• try - test-various (web logs, extended logs)

[GuillaumeGomez]

@bors try jobs=armhf-gnu,test-various,x86_64-gnu-aux

[rust-bors]

💔 Test for 38c3e03 failed: CI. Failed jobs:

• try - test-various (web logs, extended logs)

[GuillaumeGomez]

@bors try jobs=test-various

[rust-bors]

💔 Test for c5583f8 failed: CI. Failed jobs:

• try - test-various (web logs, extended logs)

[GuillaumeGomez]

Not ready yet! Just more cleanups before my next attempt: if should_panic (and not compile_fail), then we compile a binary with libtest to ensure we can actually run this test and if so, we call the other code.