[Bug c/93857] missing test for diagnostic: using integer constants in boolean context

[roland.illig at gmx dot de]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=93857

--- Comment #4 from Roland Illig <roland.illig at gmx dot de> ---
In the case of "boolean context", there are a few other diagnostics that also
contain these exact words. Therefore the tests should at least have enough
words to distinguish these diagnostics from the others.