The mitigations don't affect CPU bound benchmarks [1] which don't call into the kernel or use specific user-space mitigations, so it won't matter here.
Good point, I forgot about that one, although here there is only a single hot loop with one jump so a high chance the crossing doesn't occur, and even if it does the IPC is low enough the legacy decoder probably does OK (although it adds a cycle or two to misprediction recovery, which matters here).
[1] There are some rare exceptions, such as https://travisdowns.github.io/blog/2019/03/19/random-writes-... , but it is unlikely to matter here.