The cipher suites were apparently renamed late in the standardization
process, and we picked up the legacy name. We can't remove the old
constants, but add correctly named ones.

Fixes #32061

Change-Id: I65ee25c12c10934391af88b76b18565da67453fa
Reviewed-on: https://go-review.googlesource.com/c/go/+/205068
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>