crypto/tls: replace custom equal implementations with reflect.DeepEqual

The equal methods were only there for testing, and I remember regularly
getting them wrong while developing tls-tris. Replace them with simple
reflect.DeepEqual calls.

The only special thing that equal() would do is ignore the difference
between a nil and a zero-length slice. Fixed the Generate methods so
that they create the same value that unmarshal will decode. The
difference is not important: it wasn't tested, all checks are
"len(slice) > 0", and all cases in which presence matters are
accompanied by a boolean.

Change-Id: Iaabf56ea17c2406b5107c808c32f6c85b611aaa8
Reviewed-on: https://go-review.googlesource.com/c/144114
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Adam Langley <agl@golang.org>

ticket.go

@@ -27,31 +27,6 @@ type sessionState struct {
 	usedOldKey bool
 }
 
-func (s *sessionState) equal(i interface{}) bool {
-	s1, ok := i.(*sessionState)
-	if !ok {
-		return false
-	}
-
-	if s.vers != s1.vers ||
-		s.cipherSuite != s1.cipherSuite ||
-		!bytes.Equal(s.masterSecret, s1.masterSecret) {
-		return false
-	}
-
-	if len(s.certificates) != len(s1.certificates) {
-		return false
-	}
-
-	for i := range s.certificates {
-		if !bytes.Equal(s.certificates[i], s1.certificates[i]) {
-			return false
-		}
-	}
-
-	return true
-}
-
 func (s *sessionState) marshal() []byte {
 	length := 2 + 2 + 2 + len(s.masterSecret) + 2
 	for _, cert := range s.certificates {