xtask: Run tmt report on failure

Why tmt doesn't do this by default, I have no idea. It's also
baffling that it takes three levels of verbose i.e. `-vvv` to
get the actual test error.

But anyways it works.

Signed-off-by: Colin Walters <[email protected]>

Author: cgwalters

crates/xtask/src/xtask.rs

@@ -781,6 +781,7 @@ fn run_tmt(sh: &Shell, args: &RunTmtArgs) -> Result<()> {
     println!("========================================\n");
 
     if !all_passed {
+        cmd!(sh, "tmt run -l report -vvv").ignore_status().run()?;
         anyhow::bail!("Some tests failed");
     }