CWG2923 Note about infinite loops and execution steps

[jensmaurer]

The note in 6.9.2.3 [intro.progress] paragraph 5 is factually incorrect.

CWG asks SG1 to advise on its deposition.

See CWG2923 for details.

[gonzalobg]

SG1 conclusion (cc @ogiroux): the note can be removed. Unanimous consent.