Declare HTTPDownloaderTest as flaky #22245

Job	Run time
Cancel Previous Runs	2s
Engine (linux, x86_64)	27m 30s
Engine (macos, x86_64)	1h 32m 41s
Engine (windows, x86_64)	3m 26s
Scala Tests (linux, x86_64)	35m 43s
Scala Tests (macos, x86_64)	1h 18m 16s
Scala Tests (windows, x86_64)	43m 49s
Standard Library Tests (linux, x86_64)	28m 4s
Standard Library Tests (macos, x86_64)	36m 10s
Standard Library Tests (windows, x86_64)	14m 20s
Verify License Packages (linux, x86_64)	1m 7s
	6h 1m 8s

Provide feedback