Called from try_flush_memtable_to_sstable,
maybe_wait_for_sstable_count_reduction will wait for
compaction to catch up with memtable flush if there
the bucket to compact is inflated, having too many
sstables. In that case we don't want to add fuel
to the fire by creating yet another sstable.
Fixes#4116
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
f26e655646