refactor: make Process#kill() throw sensible errors on Windows (#9111)

Previously, calling `Process#kill()` after the process had exited would
sometimes throw a `TypeError` on Windows. After this patch, it will
throw `NotFound` instead, just like other platforms.

This patch also fixes flakiness of the `runKillAfterStatus` test on
Windows.

cli/tests/unit/process_test.ts

@@ -434,16 +434,20 @@ unitTest(
     });
     await p.status();
 
-    // On Windows the underlying Rust API returns `ERROR_ACCESS_DENIED`,
-    // which serves kind of as a catch all error code. More specific
-    // error codes do exist, e.g. `ERROR_WAIT_NO_CHILDREN`; it's unclear
-    // why they're not returned.
-    const expectedErrorType = Deno.build.os === "windows"
-      ? Deno.errors.PermissionDenied
-      : Deno.errors.NotFound;
-    assertThrows(
-      () => p.kill(Deno.Signal.SIGTERM),
-      expectedErrorType,
+    let error = null;
+    try {
+      p.kill(Deno.Signal.SIGTERM);
+    } catch (e) {
+      error = e;
+    }
+
+    assert(
+      error instanceof Deno.errors.NotFound ||
+        // On Windows, the underlying Windows API may return
+        // `ERROR_ACCESS_DENIED` when the process has exited, but hasn't been
+        // completely cleaned up yet and its `pid` is still valid.
+        (Deno.build.os === "windows" &&
+          error instanceof Deno.errors.PermissionDenied),
     );
 
     p.close();