Fixes BurntSushi#42.

This was actually fixed in commit 44d4af for BurntSushi#43, but this adds a
regression test from BurntSushi#42.

encode_test.go

@@ -423,6 +423,28 @@ func TestEncodeNestedTableArrays(t *testing.T) {
 	encodeExpected(t, "nested table arrays", value, expected, nil)
 }
 
+func TestEncodeArrayHashWithNormalHashOrder(t *testing.T) {
+	type Alpha struct {
+		V int
+	}
+	type Beta struct {
+		V int
+	}
+	type Conf struct {
+		V int
+		A Alpha
+		B []Beta
+	}
+
+	val := Conf{
+		V: 1,
+		A: Alpha{2},
+		B: []Beta{{3}},
+	}
+	expected := "V = 1\n\n[A]\n  V = 2\n\n[[B]]\n  V = 3\n"
+	encodeExpected(t, "array hash with normal hash order", val, expected, nil)
+}
+
 func encodeExpected(
 	t *testing.T, label string, val interface{}, wantStr string, wantErr error,
 ) {