Can't correctly append bytes bigger than 0x79

[alexvanin]

When appending single bytes to []byte, compiler adds extra 0x0 for all values starting from 0x80 up to 0xFF

	{
		"append bytes bigger than 0x79",
		`package foo
		func Main() []byte {
			var z []byte
			z = append(z, 0x78, 0x79, 0x80, 0x81, 0xFF)
			return z
		}`,
		[]byte{0x78, 0x79, 0x80, 0x81, 0xFF},
	},

// Expected :[]byte{0x78, 0x79, 0x80, 0x81, 0xff}
// Actual   :[]byte{0x78, 0x79, 0x80, 0x0, 0x81, 0x0, 0xff, 0x0}

Appending with z = append(z, []byte{0x78, 0x79, 0x80, 0x81, 0xFF}...) solves the issue.