Enable ARM64 cryptographic extensions in iOS library builds

Go's internal/cpu never detects ARM64 features on GOOS=ios, so AES, AES-GCM
and SHA-256 use their generic implementations on iOS and tvOS. Patch the
Go source in the Apple library build to assert the ARMv8.0 cryptographic
extensions, as Go already does for macOS.

See https://github.com/SagerNet/sing-box/issues/4486

.github/go_ios_cpu_features.patch

@@ -0,0 +1,28 @@
+--- a/src/internal/cpu/cpu_arm64_ios.go
++++ b/src/internal/cpu/cpu_arm64_ios.go
+@@ -0,0 +1,14 @@
++// Copyright 2020 The Go Authors. All rights reserved.
++// Use of this source code is governed by a BSD-style
++// license that can be found in the LICENSE file.
++
++//go:build arm64 && ios
++
++package cpu
++
++func osInit() {
++	ARM64.HasAES = true
++	ARM64.HasPMULL = true
++	ARM64.HasSHA1 = true
++	ARM64.HasSHA2 = true
++}
+--- a/src/internal/cpu/cpu_arm64_other.go
++++ b/src/internal/cpu/cpu_arm64_other.go
+@@ -2,7 +2,7 @@
+ // Use of this source code is governed by a BSD-style
+ // license that can be found in the LICENSE file.
+ 
+-//go:build arm64 && !linux && !freebsd && !android && (!darwin || ios) && !openbsd
++//go:build arm64 && !linux && !freebsd && !android && !darwin && !openbsd
+ 
+ package cpu
+