crypto/tls: document that the package supports TLS 1.2

Fixes issue 6456.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/13740047
runtime/pprof: fix profile parser in test

Fixes issue 6417.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/13843043