rpc test randomly failing

[debris]

job: https://gitlab.parity.io/parity/parity-ethereum/-/jobs/100436
pr: #9633

---- v1::tests::mocked::signing::should_check_status_of_request_when_its_resolved stdout ----
thread 'v1::tests::mocked::signing::should_check_status_of_request_when_its_resolved' panicked at 'assertion failed: `(left == right)` (left: `Some("{\"jsonrpc\":\"2.0\",\"result\":null,\"id\":1}")`, right: `Some("{\"jsonrpc\":\"2.0\",\"result\":\"0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001\",\"id\":1}")`, diff: ` Some("{\"jsonrpc\":\"2.0\",\"result\":null,\"id\":1}") Some("{\"jsonrpc\":\"2.0\",\"result\":\"0x0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001\",\"id\":1}") `)', rpc/src/v1/tests/mocked/signing.rs:207:2
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.
stack backtrace:
   0: std::sys::unix::backtrace::tracing::imp::unwind_backtrace
             at libstd/sys/unix/backtrace/tracing/gcc_s.rs:49
   1: std::sys_common::backtrace::print
             at libstd/sys_common/backtrace.rs:71
             at libstd/sys_common/backtrace.rs:59
   2: std::panicking::default_hook::{{closure}}
             at libstd/panicking.rs:211
   3: std::panicking::default_hook
             at libstd/panicking.rs:221
   4: std::panicking::rust_panic_with_hook
             at libstd/panicking.rs:475
   5: std::panicking::continue_panic_fmt
             at libstd/panicking.rs:390
   6: std::panicking::begin_panic_fmt
             at libstd/panicking.rs:345
   7: parity_rpc::v1::tests::mocked::signing::should_check_status_of_request_when_its_resolved
   8: <F as alloc::boxed::FnBox<A>>::call_box
             at libtest/lib.rs:1451
             at /checkout/src/libcore/ops/function.rs:223
             at /checkout/src/liballoc/boxed.rs:642
   9: __rust_maybe_catch_panic
             at libpanic_unwind/lib.rs:105