[roottest][io] Bring back __CLING__ guard in Hard2Stream members

[guitargeek]

Follows up on 5727e1d, bringing back a __CINT__ preprocessor guard that should have stayed and rename it to __CLING__.

Address https://github.com/root-project/root/pull/20613/files#r2590556753

[pcanal]

Thanks.

[pcanal]

Apparently we are missing something :(

[guitargeek]

Seems like it! You want to bring back the __CINT__ (and a comment) for now and try to understand the problem later?

But isn't __CINT__ a no-op now anyway? I don't understand what is going on, or why exactly the macro is required here 🙁

[pcanal]

Seems like it! You want to bring back the CINT (and a comment) for now and try to understand the problem later?

Nah ... but it looks like it was indeed no longer doing anything for that test and that the suggestion I made is the wrong thing (does not work) to accomplish the intent (ensuring that the I/O cannot/will not use the interpreter information for streaming - i.e. we don't want the test to succeed even though the Streamer function was not used).

So it looks like I need to find a better semantic replacement (and/or maybe I am lucky there is already part of the current test that does it some other way).

[github-actions]

Test Results

    21 files      21 suites   3d 16h 16m 34s ⏱️
 3 783 tests  3 782 ✅ 0 💤  1 ❌
77 532 runs  77 511 ✅ 0 💤 21 ❌

For more details on these failures, see this check.

Results for commit bb0e482.