[Support] Move raw_ostream::tie to raw_fd_ostream (#97396)
Originally, tie was introduced by D81156 to flush stdout before writing
to stderr. 030897523 reverted this due to race conditions. Nonetheless,
it does cost performance, causing an extra check in the "cold" path,
which is actually the hot path for raw_svector_ostream. Given that this
feature is only used for errs(), move it to raw_fd_ostream so that it no
longer affects performance of other stream classes.
