net/http/httptest: fix comment regarding certificate expiry
In earlier versions of Go, times were only encoded as an ASN.1 UTCTIME and
crypto/tls/generate_cert.go limited times to the maximum UTCTIME value.
Revision
050b60a3 added support for ASN.1 GENERALIZEDTIME, allowing larger
time values to be represented (per RFC 5280).
As a result, when the httptest certificate was regenerated in revision
9b2d84ef, the Not After date changed to Jan 29 16:00:00 2084 GMT. Update
the comment to reflect this.
Change-Id: I1bd66e011f2749f9372b5c7506f52ea34e264ce9
Reviewed-on: https://go-review.googlesource.com/16193
Reviewed-by: Adam Langley <agl@golang.org>