[llvm] [llvm] Report a WinHttpQueryDataAvailable failure instead of ending the body (PR #226514)

[via llvm-commits]

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Nerixyz wrote:

This can also return a timeout error. Though, realistically, it shouldn't for our use, as we only read the available bytes. Still, maybe some timer expired in between the calls.

https://github.com/llvm/llvm-project/pull/226514