Add tests for assignment evaluation orders

See https://docs.oracle.com/javase/specs/jls/se17/html/jls-15.html#jls-15.26.1

exec/ArrayIndexEvaluationOrder.java

+class ArrayIndexEvaluationOrder {
+
+    public int val;
+    public int[] arr;
+
+    public ArrayIndexEvaluationOrder init() {
+        this.arr = new int[20];
+        this.val = 0;
+
+        return this;
+    }
+
+    public int[] fetchArrWithSideEffect() {
+        val = 42;
+        return arr;
+    }
+
+    public int fetchIndexWithSideEffect() {
+        val = 21;
+        return 1;
+    }
+
+    public void check() {
+        fetchArrWithSideEffect()[fetchIndexWithSideEffect()] = 10;
+
+        System.out.println(val);
+        System.out.println(arr[1]);
+    }
+
+    public static void main(String[] args) {
+        new ArrayIndexEvaluationOrder().init().check();
+    }
+}

exec/ArrayIndexEvaluationOrder.java.out

+21
+10

exec/AssignmentEvaluationOrder.java

+class AssignmentEvaluationOrder {
+
+    public int x;
+    public int[] arr;
+
+    public AssignmentEvaluationOrder init() {
+        arr = new int[20];
+        x = 10;
+
+        return this;
+    }
+
+    public void check() {
+        arr[x = 5] = x;
+
+        System.out.println(arr[5]);
+    }
+
+    public static void main(String[] args) {
+        new AssignmentEvaluationOrder().init().check();
+    }
+}
+

exec/AssignmentEvaluationOrder.java.out

+5