parser: fix a & b == c precedence

vlib/builtin/int_test.v

@@ -66,6 +66,15 @@ fn test_str_methods() {
 	assert u64(-1).str() == '18446744073709551615'
 }
 
+fn test_and() {
+	c:=[1,2,3,4,5]
+	assert c[0] & 1 != 0
+	assert c[1] & 1 == 0
+	assert c[2] & 1 != 0
+	assert c[3] & 1 == 0
+	assert c[4] & 1 != 0
+}
+
 /*
 fn test_cmp() {
 	assert 1 ≠ 2