test runner: refresh display before running test

This makes it so that when a test fails quickly, and writes output, it
will do so after the test name is printed.

lib/std/special/test_runner.zig

@@ -15,6 +15,7 @@ pub fn main() anyerror!void {
     for (test_fn_list) |test_fn, i| {
         var test_node = root_node.start(test_fn.name, null);
         test_node.activate();
+        progress.refresh();
         if (test_fn.func()) |_| {
             ok_count += 1;
             test_node.end();