Cherry pick PR #2118: Fix the persistent_cookie blackbox test. #372

Job	Run time
linux / initialize	45s
linux / docker-build-image	32s
linux / docker-unittest-image	33s
linux / x64_devel	13m 23s
linux / x64_debug	10m 41s
linux / x64_qa	9m 45s
linux / x64_gold	8m 45s
linux / sbversion-12_devel	13m 11s
linux / sbversion-12_debug	10m 38s
linux / sbversion-12_qa	8m 28s
linux / sbversion-12_gold	8m 38s
linux / x64_unit_test	23m 43s
linux / x64_integration_test	10m 42s
linux / sbversion-12_unit_test	26m 36s
linux / sbversion-12_integration_test	10m 38s
linux / ${{ matrix.name }}_on_device_${{ matrix.type }}	0s
	2h 36m 58s

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