stop removing backslashes in shell

[keith-turner]

fixes #3367

[keith-turner]

Created this as a draft because I am not sure what functionality this might break in jshell. Also this changes shell behavior that has been different since 2.1.0. Test this and it does work, the jline line reader no longer turns \x00 into x00

[keith-turner]

Reworked this in commit 82900a9 to make Accumulo look for the jline option and set it.

Test that commit by inserting the following data in jshell.

jshell> client.tableOperations().create("test"); var writer=client.createBatchWriter("test"); Mutation m = new Mutation("r1"); m.at().family(new byte[]{'a',0,'b'}).qualifier("q").put("v1"); writer.addMutation(m); writer.close();

Then made the following change in accumulo-env.sh

JAVA_OPTS=(
  '-XX:OnOutOfMemoryError=kill -9 %p'
  '-XX:-OmitStackTraceInFastThrow'
  '-Djava.net.preferIPv4Stack=true'
  '-Dorg.jline.reader.props.disable-event-expansion=on'
  "-Daccumulo.native.lib.path=${lib}/native"
  "${accumulo_initial_opts[@]}"
)

After that, ran the shell and jline is no longer removing \

root@uno> scan -t test -c a\x00b
r1 a\x00b:q []	v1