Remove obsolete test programs

rt/tests/check.sh

-#!/bin/bash
-set -e
-rm mixed_fibo || true
-make mixed_fibo
-
-for i in {0..100}
-do
-  ./mixed_fibo
-done
-echo "ok"

rt/tests/main.cpp

-#include <typon/task.hpp>
-
-#include <cstdio>
-
-using namespace typon;
-
-Task<int> fibo(int n) {
-  if (n < 2) {
-    co_return n;
-  }
-  int a = co_await fibo(n - 1);
-  int b = co_await fibo(n - 2);
-  co_return a + b;
-}
-
-int main() {
-  int result = fibo(40).call();
-  printf("%d\n", result);
-}

rt/tests/test_discard.cpp

-#include <typon/task.hpp>
-
-#include <cstdio>
-
-using namespace typon;
-
-Task<int> add(int a, int b) {
-  printf("add(%d, %d)\n", a, b);
-  co_return a + b;
-}
-
-Task<int> call_add_but_ignore_result(int a, int b) {
-  co_await add(a, b).discard();
-  co_return 1;
-}
-
-int main() {
-  call_add_but_ignore_result(2, 3).call_discard();
-}

rt/tests/test_inline.cpp

-#include <typon/task.hpp>
-
-#include <cstdio>
-
-using namespace typon;
-
-Task<int> add(int a, int b) {
-  co_return a + b;
-}
-
-Task<int> add_indirection(int a, int b) {
-  co_return co_await add(a, b);
-}
-
-int main() {
-  int result = add_indirection(2, 3).call();
-  return result;
-}