I don't think that is the case for modern (last 8 years or so) Intel processors. For example, I'm under the impression that gcc's __builtin_expect only affects the layout of the generated code. However I'd love to learn something new here; do you have a source or any additional info you could share?
The hints are purely for the compiler. When branch probabilities are available (either via heuristics, annotations or profile data), it will optimize hot paths differently from cold paths. For example it might be more aggressive with inlinig or vice versa optimize for size. Also will attempt to put cold code in separate pages so that it doesn't get pollute the cache. Also non taken braches are marginally "faster" than taken so it is worth, when possible to put hot code in the non taken branch.
I'm not a compiler writer, I'm sure there is more.
Compiler writers are smart people and can layout code to give the CPU the right hints, so long as they know what the CPU does. CPU manufactures want the compilers writers to do this as the compiler is a significant factor in making one CPU faster than the competition in benchmarks.