[clang] Revisit tests for CWG2917 and CWG3005 after Core updates (#181513)
This patch revisits the status of tests for two aforementioned Core
issues.
I agree with the analysis in #170410, so no changes are made to CWG2917
test.
In case of CWG3005, Core approved the 2025-09-12 proposed resolution,
which the test was written against in the first place.
Fixes #170410