machine: use new internal/binary package

The encoding/binary package in Go 1.23 imports the slices package, which
results in circular import when imported from the machine package.
Therefore, encoding/binary cannot be used in the machine package.

This commit fixes that by introducing a new internal/binary package that
is just plain Go code without dependencies. It can be safely used
anywhere (including the runtime if needed).

src/internal/binary/binary.go

@@ -0,0 +1,32 @@
+// Package binary is a lightweight replacement package for encoding/binary.
+package binary
+
+// This file contains small helper functions for working with binary data.
+
+var LittleEndian = littleEndian{}
+
+type littleEndian struct{}
+
+// Encode data like encoding/binary.LittleEndian.Uint16.
+func (littleEndian) Uint16(b []byte) uint16 {
+	return uint16(b[0]) | uint16(b[1])<<8
+}
+
+// Store data like binary.LittleEndian.PutUint16.
+func (littleEndian) PutUint16(b []byte, v uint16) {
+	b[0] = byte(v)
+	b[1] = byte(v >> 8)
+}
+
+// Append data like binary.LittleEndian.AppendUint16.
+func (littleEndian) AppendUint16(b []byte, v uint16) []byte {
+	return append(b,
+		byte(v),
+		byte(v>>8),
+	)
+}
+
+// Encode data like encoding/binary.LittleEndian.Uint32.
+func (littleEndian) Uint32(b []byte) uint32 {
+	return uint32(b[0]) | uint32(b[1])<<8 | uint32(b[2])<<16 | uint32(b[3])<<24
+}