Fix: print diagnostics to stdout in s2n_resume_test

[ravindran-dev]

Goal

Ensure diagnostic messages in s2n_resume_test are visible when running tests through CTest.

Why

CTest does not reliably surface output written to stderr, even when using --output-on-failure.
As a result, important diagnostic hints in s2n_resume_test were not visible whenever the test failed.

How

Replaced all fprintf(stderr, ...) diagnostic messages in s2n_resume_test with printf(...) so the output goes to stdout, which CTest reliably displays.

Callouts

• No functional logic changed - only output streams.

• This improves developer visibility during failures without altering test behavior.

Testing

Build

cd /home/ravi/s2n-tls
rm -rf build
mkdir build
cd build

cmake .. -DCMAKE_BUILD_TYPE=Debug
cmake --build . -j8

Test

ctest -R s2n_resume_test --output-on-failure

Result

Diagnostic messages now appear correctly in test output.

Related

refs: #4112

Output:

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