all: move internal/x to vendor/golang.org/x and revendor using 'go mod vendor'

This also updates the vendored-in versions of several packages: 'go
mod vendor' selects a consistent version of each module, but we had
previously vendored an ad-hoc selection of packages.

Notably, x/crypto/hkdf was previously vendored in at a much newer
commit than the rest of x/crypto. Bringing the rest of x/crypto up to
that commit introduced an import of golang.org/x/sys/cpu, which broke
the js/wasm build, requiring an upgrade of x/sys to pick up CL 165749.

Updates #30228
Updates #30241
Updates #25822

Change-Id: I5b3dbc232b7e6a048a158cbd8d36137af1efb711
Reviewed-on: https://go-review.googlesource.com/c/go/+/164623
Reviewed-by: Filippo Valsorda <filippo@golang.org>

cipher_suites.go

@@ -14,8 +14,8 @@ import (
 	"crypto/sha1"
 	"crypto/sha256"
 	"crypto/x509"
+	"golang.org/x/crypto/chacha20poly1305"
 	"hash"
-	"internal/x/crypto/chacha20poly1305"
 )
 
 // a keyAgreement implements the client and server side of a TLS key agreement

handshake_messages.go

@@ -6,7 +6,7 @@ package tls
 
 import (
 	"fmt"
-	"internal/x/crypto/cryptobyte"
+	"golang.org/x/crypto/cryptobyte"
 	"strings"
 )
 

key_schedule.go

@@ -8,10 +8,10 @@ import (
 	"crypto/elliptic"
 	"crypto/hmac"
 	"errors"
+	"golang.org/x/crypto/cryptobyte"
+	"golang.org/x/crypto/curve25519"
+	"golang.org/x/crypto/hkdf"
 	"hash"
-	"internal/x/crypto/cryptobyte"
-	"internal/x/crypto/curve25519"
-	"internal/x/crypto/hkdf"
 	"io"
 	"math/big"
 )

ticket.go

@@ -12,7 +12,7 @@ import (
 	"crypto/sha256"
 	"crypto/subtle"
 	"errors"
-	"internal/x/crypto/cryptobyte"
+	"golang.org/x/crypto/cryptobyte"
 	"io"
 )