LOGF/LOGF_COLOR always ran fmt::sprintf even when the output was discarded; at
emulator log volume the formatting alone costs frames. Add Log::IsSilent() and
short-circuit before formatting. Behavior-preserving on all platforms (it only
skips work whose result is thrown away); before init it reports non-silent so
early logs still print.
(cherry picked from commit 1749e0fc68ae4290055fb12f72c9bb4baf466190)
Abdullah K.
31ea0081a9