tests: add a multilevel pointer cast test too

vlib/v/tests/pointers_multilevel_casts_test.v

@@ -0,0 +1,40 @@
+struct Struct {}
+
+fn test_byte_pointer_casts() {
+	unsafe {
+		pb := &byte(1)
+		ppb := &&byte(2)
+		pppb := &&&byte(3)
+		ppppb := &&&&byte(4)
+		assert voidptr(pb).str() == '1'
+		assert voidptr(ppb).str() == '2'
+		assert voidptr(pppb).str() == '3'
+		assert voidptr(ppppb).str() == '4'
+	}
+}
+
+fn test_char_pointer_casts() {
+	unsafe {
+		pc := &char(5)
+		ppc := &&char(6)
+		pppc := &&&char(7)
+		ppppc := &&&&char(8)
+		assert voidptr(pc).str() == '5'
+		assert voidptr(ppc).str() == '6'
+		assert voidptr(pppc).str() == '7'
+		assert voidptr(ppppc).str() == '8'
+	}
+}
+
+fn test_struct_pointer_casts() {
+	unsafe {
+		ps := &Struct(9)
+		pps := &&Struct(10)
+		ppps := &&&Struct(11)
+		pppps := &&&&Struct(12)
+		assert voidptr(ps).str() == '9'
+		assert voidptr(pps).str() == 'a'
+		assert voidptr(ppps).str() == 'b'
+		assert voidptr(pppps).str() == 'c'
+	}
+}