Skip the fast-append key comparison unless we've previously appended
data to the tree.
Comment cleanup.
Don't do an append test regardless if searching the tree, but more
importantly, don't clear the "appending" flag for a read operation.
This makes no difference in terms of performance, but means we don't
let read operations interfere with our understanding of an appending
workload.
Merge pull request #1003 from wiredtiger/row-skip-append-check

Row skip append check