Fixed leak and removed no-shuffle tag in ticker_test.dart

[Swiftaxe]

This PR fixed the problem that has prevented ticker_test.dart being shuffled. Part of #85160.

One test paused the app life cycle state which broke other tests when shuffled.
This PR resumes the app life cycle state before the test finishes. Some duplicated lines of code is refactored into method setAppLifeCycleState() as well.

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• I added new tests to check the change I am making or feature I am adding, or Hixie said the PR is test-exempt.
• All existing and new tests are passing.

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[SigmaAD]

@googlebot I consent.

[gspencergoog]