* perf(fex): answer raw stat, readlink and statx syscalls through the proot fast path
FEX issues newfstatat, readlinkat and statx as raw syscall() calls, which skipped the libc wrappers the fast path hooks and fell through to ptrace. Route them through libblfastpath the same way raw openat already is, and keep the fast path's own /proc/self/exe lookup off the hooked syscall().
* test(fex): keep the raw lookup test passing on kernels without statx