Auto merge of #52181 - QuietMisdreavus:panicked-tester, r=GuillaumeGomez

rustdoc: set panic output before starting compiler thread pool

When the compiler was updated to run on a thread pool, rustdoc's processing of compiler/doctest stderr/stdout was moved into each compiler thread. However, this caused output of the test to be lost if the test failed at *runtime* instead of compile time. This change sets up the `set_panic` call and output bomb before starting the compiler thread pool, so that the `Drop` call that writes back to the test's stdout happens after the test runs, not just after it compiles.

Fixes rust-lang/rust#51162

Author: bors

src/header.rs

@@ -392,18 +392,20 @@ impl TestProps {
 
             if let Some(code) = config.parse_failure_status(ln) {
                 self.failure_status = code;
-            } else {
-                self.failure_status = match config.mode {
-                    Mode::RunFail => 101,
-                    _ => 1,
-                };
             }
 
             if !self.run_rustfix {
                 self.run_rustfix = config.parse_run_rustfix(ln);
             }
         });
 
+        if self.failure_status == -1 {
+            self.failure_status = match config.mode {
+                Mode::RunFail => 101,
+                _ => 1,
+            };
+        }
+
         for key in &["RUST_TEST_NOCAPTURE", "RUST_TEST_THREADS"] {
             if let Ok(val) = env::var(key) {
                 if self.exec_env.iter().find(|&&(ref x, _)| x == key).is_none() {