Server Push is not more performant than regular HTTP/2 test
for this demo. I will produce a new demo page where Server Push
is clearly a better choice and consistently faster.

This reverts commit 3e967e1d.

Change-Id: Iace26e17714c0eca52785fc04d410df041e56415
Reviewed-on: https://go-review.googlesource.com/38608Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>