cli: Example_demo failed under stress

SHA: https://github.com/cockroachdb/cockroach/commits/87589eca54b446956255161ade72a7fd912ccedb

Parameters:

TAGS=
GOFLAGS=

To repro, try:

# Don't forget to check out a clean suitable branch and experiment with the
# stress invocation until the desired results present themselves. For example,
# using stressrace instead of stress and passing the '-p' stressflag which
# controls concurrency.
./scripts/gceworker.sh start && ./scripts/gceworker.sh mosh
cd ~/go/src/github.com/cockroachdb/cockroach && \
make stress TESTS=Example_demo PKG=github.com/cockroachdb/cockroach/pkg/cli TESTTIMEOUT=5m STRESSFLAGS='-stderr=false -maxtime 20m -timeout 10m'

Failed test: https://teamcity.cockroachdb.com/viewLog.html?buildId=932309&tab=buildLog

=== RUN   Example_demo
[demo -e show database]
[demo -e show application_name]
[demo --format=table -e show database]
[demo -e select 1 as "1" -e select 3 as "3"]
[demo --echo-sql -e select 1 as "1"]
[demo --set=errexit=0 -e select nonexistent -e select 123 as "123"]
[demo startrek -e show databases]
E180929 05:22:27.233908 1 cli/error.go:230  had 13 ranges at startup, expected 22
Error: had 13 ranges at startup, expected 22
[demo startrek -e show databases --format=table]
E180929 05:22:27.664192 28564 storage/queue.go:788  [n1,split,s1,r24/1:/{Table/53-Max}] unable to split [n1,s1,r24/1:/{Table/53-Max}] at key "/Table/54": split at key /Table/54 failed: result is ambiguous (server shutdown)
--- FAIL: Example_demo (12.98s)
got:
demo -e show database
database
defaultdb
demo -e show application_name
application_name
$ cockroach demo
demo --format=table -e show database
  database
+-----------+
  defaultdb
(1 row)
demo -e select 1 as "1" -e select 3 as "3"
1
1
3
3
demo --echo-sql -e select 1 as "1"
> select 1 as "1"
1
1
demo --set=errexit=0 -e select nonexistent -e select 123 as "123"
pq: column "nonexistent" does not exist
123
123
demo startrek -e show databases
had 13 ranges at startup, expected 22
demo startrek -e show databases --format=table
  database_name
+---------------+
  defaultdb
  postgres
  startrek
  system
(4 rows)
want:
demo -e show database
database
defaultdb
demo -e show application_name
application_name
$ cockroach demo
demo --format=table -e show database
  database
+-----------+
  defaultdb
(1 row)
demo -e select 1 as "1" -e select 3 as "3"
1
1
3
3
demo --echo-sql -e select 1 as "1"
> select 1 as "1"
1
1
demo --set=errexit=0 -e select nonexistent -e select 123 as "123"
pq: column "nonexistent" does not exist
123
123
demo startrek -e show databases
database_name
defaultdb
postgres
startrek
system
demo startrek -e show databases --format=table
  database_name
+---------------+
  defaultdb
  postgres
  startrek
  system
(4 rows)

cockroachdb / cockroach

cli: Example_demo failed under stress #30783