[7.16](backport #28998) Add null (\u0000) as a valid line terminator

[mergify]

This is an automatic backport of pull request #28998 done by Mergify.

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[elasticmachine]

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• Start Time: 2021-11-22T09:44:24.761+0000

• Duration: 144 min 55 sec

• Commit: 26e3061

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Test	Results
Failed	0
Passed	55348
Skipped	5317
Total	60665

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