Allow later globs to override pass/fail status of earlier globs

[dtolnay]

For example the following setup:

// test/compiletest.rs

#[test]
fn ui() {
    let t = trybuild::TestCases::new();
    t.compile_fail("tests/ui/*.rs");
    t.pass("tests/ui/ok.rs");
}

// tests/ui/fail.rs

fn main() {
    let;
}

// tests/ui/ok.rs

fn main() {}

Currently trybuild would build ok.rs twice, expecting it to both pass and fail, which is nonsensical.

test tests/ui/fail.rs [should fail to compile] ... wip

NOTE: writing the following output to `wip/fail.stderr`.
Move this file to `tests/ui/fail.stderr` to accept it as correct.
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈
error: expected pattern, found `;`
 --> tests/ui/fail.rs:2:8
  |
2 |     let;
  |        ^ expected pattern
┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈┈

test tests/ui/ok.rs [should fail to compile] ... error
Expected test case to fail to compile, but it succeeded.

test tests/ui/ok.rs [should pass] ... ok

test ui ... FAILED

Instead the last glob that applies to a particular file should be the only one that takes effect.