coverage: Migrate tests/run-coverage into tests/coverage

tests/coverage/panic_unwind.rs

@@ -0,0 +1,31 @@
+#![allow(unused_assignments)]
+// failure-status: 101
+
+fn might_panic(should_panic: bool) {
+    if should_panic {
+        println!("panicking...");
+        panic!("panics");
+    } else {
+        println!("Don't Panic");
+    }
+}
+
+fn main() -> Result<(), u8> {
+    let mut countdown = 10;
+    while countdown > 0 {
+        if countdown == 1 {
+            might_panic(true);
+        } else if countdown < 5 {
+            might_panic(false);
+        }
+        countdown -= 1;
+    }
+    Ok(())
+}
+
+// Notes:
+//   1. Compare this program and its coverage results to those of the similar tests `abort.rs` and
+//      `try_error_result.rs`.
+//   2. Since the `panic_unwind.rs` test is allowed to unwind, it is also allowed to execute the
+//      normal program exit cleanup, including writing out the current values of the coverage
+//      counters.