[NFC] Clean up free function testcases

[LU-JOHN]

Only have output on failure.

[aelovikov-intel]

I'd suggest changing it like

bool checkUSM(..., int line = __builtin_LINE()) {
    ...
    std::cout << "checkUSM failed, called from line " << line << std::endl;
    return false;
}

Maybe also use __PRETTY_FUNCTION__, although that doesn't work with MSVC as host compiler, but we probably don't care much.