encoding/asn1: be stricter by reserialising parsed times.
The time package does normalisation of times: for example day zero is
converted to the last day of the previous month and the 31st of February
is moved into March etc. This makes the ASN.1 parsing a little
worryingly lax.
This change causes the parser to reserialise parsed times to ensure that
they round-trip correctly and thus were not normalised.
Fixes #11134.
Change-Id: I3988bb95153a7b33d64ab861fbe51b1a34a359e9
Reviewed-on: https://go-review.googlesource.com/11094
Run-TryBot: Adam Langley <agl@golang.org>
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>