http2: don't sniff Request.Body on 100-continue requests in Transport
http2: don't sniff Request.Body on 100-continue requests in Transport

Tests in net/http: TestNoSniffExpectRequestBody_h2

Updates golang/go#16002

Change-Id: Ib5255c14f0a8fdafd36077b86442dff213815567
Reviewed-on: https://go-review.googlesource.com/30150
Run-TryBot: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>
TryBot-Result: Gobot Gobot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Ian Lance Taylor <87e9c6d529889242b7e184afb632328636553ab4@golang.org>

golang/net