Fix Clang sapphire rapids march flag

[imciner2]

A copy-paste error slipped in during the changes to how the Sapphire Rapids architecture flags were guarded in #4192, so it turns out Clang was never being told to use the Sapphire Rapids, and instead was just using Cooperlake instead.

[martin-frbg]

Thanks, totally missed that - seems sometimes the mind reads what it expects to read rather than what the actual code/text is