[release-branch.go1.21] all: tidy dependency versioning after release

Done with:

go get golang.org/x/net@internal-branch.go1.21-vendor
go mod tidy
go mod vendor
go generate net/http  # zero diff since CL 534235 already did this

For golang#63417.
For golang#63427.
For CVE-2023-39325.

Change-Id: Ib258e0d8165760a1082e02c2f4c5ce7d2a3c3c90
Reviewed-on: https://go-review.googlesource.com/c/go/+/534415
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>

src/cmd/internal/moddeps/moddeps_test.go

@@ -33,8 +33,6 @@ import (
 // See issues 36852, 41409, and 43687.
 // (Also see golang.org/issue/27348.)
 func TestAllDependencies(t *testing.T) {
-	t.Skip("TODO(#63427): 1.21.3 contains unreleased changes from vendored modules")
-
 	goBin := testenv.GoToolPath(t)
 
 	// Ensure that all packages imported within GOROOT