comm: implement and test correct handling of repeated flags

src/uu/comm/src/comm.rs

@@ -178,6 +178,7 @@ pub fn uu_app() -> Command {
         .about(ABOUT)
         .override_usage(format_usage(USAGE))
         .infer_long_args(true)
+        .args_override_self(true)
         .arg(
             Arg::new(options::COLUMN_1)
                 .short('1')

tests/by-util/test_comm.rs

@@ -75,6 +75,14 @@ fn total_with_suppressed_regular_output() {
         .stdout_is_fixture("ab_total_suppressed_regular_output.expected");
 }
 
+#[test]
+fn repeated_flags() {
+    new_ucmd!()
+        .args(&["--total", "-123123", "--total", "a", "b"])
+        .succeeds()
+        .stdout_is_fixture("ab_total_suppressed_regular_output.expected");
+}
+
 #[test]
 fn total_with_output_delimiter() {
     new_ucmd!()