tests: add `for` tests of labelled continue and break (#9189)

vlib/v/tests/for_label_continue_break_test.v

@@ -0,0 +1,82 @@
+fn test_for_c_label_continue_break() {
+	mut rets := []int{}
+	outer: for i := 4; true; i++ {
+		println(i)
+		rets << i
+		for {
+			if i < 7 {
+				continue outer
+			} else {
+				break outer
+			}
+		}
+	}
+	assert rets.len == 4
+	assert rets[0] == 4
+	assert rets[1] == 5
+	assert rets[2] == 6
+	assert rets[3] == 7
+}
+
+fn test_for_in_array_label_continue_break() {
+	mut rets := []int{}
+	arr := [4, 5, 6, 7, 8, 9]
+	outer: for i in arr {
+		println(i)
+		rets << i
+		for {
+			if i < 7 {
+				continue outer
+			} else {
+				break outer
+			}
+		}
+	}
+	assert rets.len == 4
+	assert rets[0] == 4
+	assert rets[1] == 5
+	assert rets[2] == 6
+	assert rets[3] == 7
+}
+
+fn test_for_in_fixed_array_label_continue_break() {
+	mut rets := []int{}
+	arr := [4, 5, 6, 7, 8, 9]!
+	outer: for i in arr {
+		println(i)
+		rets << i
+		for {
+			if i < 7 {
+				continue outer
+			} else {
+				break outer
+			}
+		}
+	}
+	assert rets.len == 4
+	assert rets[0] == 4
+	assert rets[1] == 5
+	assert rets[2] == 6
+	assert rets[3] == 7
+}
+
+fn test_for_in_map_label_continue_break() {
+	mut rets := []string{}
+	m := map{'a': 4, 'b': 5, 'c': 6, 'd': 7, 'e': 8, 'f': 9}
+	outer: for k, v in m {
+		println('$k, $v')
+		rets << '$k, $v'
+		for {
+			if v < 7 {
+				continue outer
+			} else {
+				break outer
+			}
+		}
+	}
+	assert rets.len == 4
+	assert rets[0] == 'a, 4'
+	assert rets[1] == 'b, 5'
+	assert rets[2] == 'c, 6'
+	assert rets[3] == 'd, 7'
+}