test(http2): expand coverage for http2_client (#999) #1482

Job	Run time
Minimal Build (Fast Feedback)	2m 40s
Sanitizers (AddressSanitizer)	15m 40s
windows-2022 / msvc	19m 45s
Sanitizers (UndefinedBehaviorSanitizer)	12m 50s
ubuntu-24.04 / gcc	10m 54s
Sanitizers (ThreadSanitizer)	16m 44s
macos-15 / clang	7m 46s
ubuntu-24.04 / clang	10m 41s
Test Downstream Compatibility	6m 43s
	1h 43m 43s

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