Revert "net/http: close accepted connection"
This reverts CL 353714.
The change closes accepted connection also in graceful shutdown which
breaks the fix for #33313 (and apparent duplicate #36819).
The proper fix should close accepted connection only if server is closed
but not in graceful shutdown.
Updates #48642
Change-Id: I2f7005f3f3037e6563745731bb2693923b654004
GitHub-Last-Rev:
f6d885aa37e793811c1624f73a3d90bc733db048
GitHub-Pull-Request: golang/go#52823
Reviewed-on: https://go-review.googlesource.com/c/go/+/405454
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>