Added regression tests for #10020 / #10081 / #10243.
The above PRs fixed some crashes due to an asserting,
see function `clientHasPendingReplies` (introduced in #9166).
This commit added some tests to cover the above scenario.
These tests will all fail in #9166, althought fixed not,
there is value in adding these tests to cover and verify
the changes. And it also can cover #8868 (verify the logs).
Other changes:
1. Reduces the wait time in `waitForBgsave` and `waitForBgrewriteaof`
from 1s to 50ms, which should reduce the time for some tests.
2. Improve the test infra to print context when `assert_match` fails.
3. Improve the test infra to print `$error` when `assert_error` fails.
```
Expected an error matching 'ERR*' but got 'OK' (context: type eval line 4 cmd {assert_error "ERR*" {r set a b}} proc ::test)
```
62c8be28ee