High tag number form may not be used for tag numbers that fit in low tag number
form.

Change-Id: I93edde0e1f86087047e0b3f2e55d6180b01e78bf
Reviewed-on: https://go-review.googlesource.com/18224Reviewed-by: Adam Langley <agl@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>