Fix tests for pt-stalk, so they can work with 8.0

export PERCONA_TOOLKIT_SANDBOX=$HOME/mysqlpackages/Percona-Server-8.0.25-15-Linux.x86_64.glibc2.17
export PERCONA_TOOLKIT_BRANCH=/home/sveta/src/percona-toolkit
export BRANCH=$(git rev-parse --abbrev-ref HEAD)
export MYSQL_VERSION=8.0
export LOG_FILE=~/${BRANCH}-${MYSQL_VERSION}.log
sandbox/test-env restart
prove -vw --trap --timer t/pt-stalk/

[15:12:09] t/pt-stalk/option_sanity.t .. 
ok 1 - Default --verbose=2
1..1
ok      310 ms ( 0.00 usr  0.00 sys +  0.31 cusr  0.06 csys =  0.37 CPU)
[15:12:10] t/pt-stalk/plugin.t ......... 
ok 1 - Exit 0
ok 2 - before_stalk hook called
ok 3 - before_collect hook called
ok 4 - after_collect hook called
ok 5 - after_collect_sleep hook called
ok 6 - after_stalk hook called
ERROR: Tables are different on slave1: mysql.proxies_priv
ERROR: Tables are different on slave2: mysql.proxies_priv
not ok 7 - Sandbox servers

#   Failed test 'Sandbox servers'
#   at t/pt-stalk/plugin.t line 73.
Bailout called.  Further testing stopped:  t/pt-stalk/plugin.t broke the sandbox
Bail out!  t/pt-stalk/plugin.t broke the sandbox
FAILED--Further testing stopped: t/pt-stalk/plugin.t broke the sandbox

$ prove -vw --trap --timer t/pt-stalk/pt-stalk.t 
[15:15:03] t/pt-stalk/pt-stalk.t .. 
ok 1 - Cannot connect to MySQL
ok 2 - Exit 1
...
# /home/sveta/src/percona-toolkit/bin/pt-stalk --no-stalk --iterations=1 --host=127.0.0.1 --port=2902 --user=msandbox --password=msandbox --sleep 0 --run-time=10 --dest /tmp/pt-stalk.collect.683750 --log /tmp/pt-stalk.log.683750 --iterations=1  --run-time=2 --pid /tmp/pt-stalk.pid.683750 --defaults-file=/tmp/2902/my.sandbox.cnf >/tmp/pt-stalk.log.683750 2>&1
not ok 46 - MySQL 5.7 SLAVE STATUS
#   Failed test 'MySQL 5.7 SLAVE STATUS'
#   at t/pt-stalk/pt-stalk.t line 756.
...
ERROR: Tables are different on slave1: mysql.proxies_priv
ERROR: Tables are different on slave2: mysql.proxies_priv
not ok 50 - Sandbox servers

#   Failed test 'Sandbox servers'
#   at t/pt-stalk/pt-stalk.t line 837.
Bailout called.  Further testing stopped:  t/pt-stalk/pt-stalk.t broke the sandbox
Bail out!  t/pt-stalk/pt-stalk.t broke the sandbox
FAILED--Further testing stopped: t/pt-stalk/pt-stalk.t broke the sandbox