Ensure all public PipeWriters return zero'd memory

HttpResponse.PipeWriter.GetMemory/Span pulls from the configured memory pool. The default pool does not zero memory. This can be problematic if the caller does not overwrite every bit.

Proposal: Audit AspNetCore and ensure all HttpResponse.PipeWriter instances are configured with a pool that zeros memory.

Some instances:
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Servers/IIS/IIS/src/Core/IISHttpContext.FeatureCollection.cs#L197
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Servers/HttpSys/src/FeatureContext.cs#L380
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Hosting/TestHost/src/HttpContextBuilder.cs#L46
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Servers/Kestrel/Core/src/Internal/Http/HttpProtocol.cs#L248
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Middleware/ResponseCompression/src/ResponseCompressionBody.cs#L90
https://github.com/aspnet/AspNetCore/blob/4aebd29abca80242f5ff9e89e07d4f1b28788a44/src/Http/Http/src/StreamResponseBodyFeature.cs#L62

Audit the HttpResponse.PipeWriter instances named in IISHttpContext.FeatureCollection.cs, FeatureContext.cs, HttpContextBuilder.cs, HttpProtocol.cs, ResponseCompressionBody.cs, and StreamResponseBodyFeature.cs. Start by comparing how each instance obtains its memory pool. Done means all public PipeWriter GetMemory/Span paths use a pool that returns zeroed memory.

Written by the indexing model from the issue text.