Fix some spammy trace events (release-7.1)

[sfc-gh-anoyes]

Cherry pick #7296 to release-7.1

Previously CycleTest was adding a parent span to 99% of transactions instead of the intended 1%, and some retry loops in GlobalConfig did not perform exponential backoff.

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Please check each of the following things and check all boxes before accepting a PR.

• The PR has a description, explaining both the problem and the solution.
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• This change/bugfix is a cherry-pick from the next younger branch (younger release-branch or main if this is the youngest branch)
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[fdb-windows-ci]

Doxense CI Report for Windows 10

• Commit ID: 3a5d9b3
• Result: ✔️ SUCCEEDED
• Build Logs (available for 30 days)

[foundationdb-ci]

AWS CodeBuild CI Report for Linux CentOS 7

• CodeBuild project: foundationdb-pr-cluster-tests
• Commit ID: 3a5d9b3
• Result: FAILED
• Error: Error while executing command: ninja -v -C build_output -j ${NPROC} all packages strip_targets. Reason: exit status 1
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[foundationdb-ci]

AWS CodeBuild CI Report for macOS BigSur 11.5.2

• CodeBuild project: foundationdb-pr-macos
• Commit ID: 3a5d9b3
• Result: SUCCEEDED
• Error: N/A
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[foundationdb-ci]

AWS CodeBuild CI Report for Linux CentOS 7

• CodeBuild project: foundationdb-pr
• Commit ID: 3a5d9b3
• Result: SUCCEEDED
• Error: N/A
• Build Logs (available for 30 days)