Bug 1688827 [wpt PR 27325] - Test cases where request body gets used before network fallback, a=testonly

Automatic update from web-platform-tests
Test cases where request body gets used before network fallback (#27325)

Tests for whatwg/fetch#1144 and w3c/ServiceWorker#1563.

Co-authored-by: Yutaka Hirano <yhiranochrmomium.org>
Co-authored-by: Anne van Kesteren <annevkannevk.nl>
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wpt-commits: c30545df6a50c61f3673ed952c78c0a607100d45
wpt-pr: 27325

UltraBlame original commit: 2472b38eb2f886421d5a062314a87dc33029a393

Author: marco-c