test: improve pod failover test

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What type of PR is this?

Uncomment only one /kind <> line, hit enter to put that in a new line, and remove leading whitespaces from that line:

/kind api-change
/kind bug
/kind cleanup
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake

/kind test

What this PR does / why we need it:

test: improve pod failover test, use kubectl wait command instead of for

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

Release note:

none