parser: remove support for a recovery test case

I don't understand the idea here of this kind of recovery. If we
want to resurrect this test case we need some comments on it to explain
the purpose, example use cases, expected behavior, etc.

lib/std/zig/parser_test.zig

@@ -4187,16 +4187,6 @@ test "recovery: invalid container members" {
     });
 }
 
-//test "recovery: invalid parameter" {
-//    try testError(
-//        \\fn main() void {
-//        \\    a(comptime T: type)
-//        \\}
-//    , &[_]Error{
-//        .expected_token,
-//    });
-//}
-
 //test "recovery: extra '}' at top level" {
 //    try testError(
 //        \\}}}