Fix rubocop offenses in spec: use Kernel.sleep stub, compact test

Author: comandeo-mongo

spec/mongo/session/with_transaction_timeout_spec.rb

@@ -43,7 +43,7 @@
     allow(session).to receive(:commit_transaction) do
       session.instance_variable_set(:@state, Mongo::Session::TRANSACTION_COMMITTED_STATE)
     end
-    allow_any_instance_of(Mongo::Session::WithTransactionRunner).to receive(:sleep)
+    allow(Kernel).to receive(:sleep)
   end
 
   # Stubs Mongo::Utils.monotonic_time: first `initial_calls` invocations
@@ -234,19 +234,14 @@ def make_commit_overload_error
 
       it 'retries and succeeds (does not raise TimeoutError)' do
         allow(Mongo::Utils).to receive(:monotonic_time).and_return(0.0)
-
-        call_count = 0
+        calls = 0
         allow(session).to receive(:commit_transaction) do
-          call_count += 1
-          raise commit_error if call_count == 1
+          calls += 1
+          raise commit_error if calls == 1
 
           session.instance_variable_set(:@state, Mongo::Session::TRANSACTION_COMMITTED_STATE)
         end
-
-        result = session.with_transaction(timeout_ms: 0) do
-          session.instance_variable_set(:@state, Mongo::Session::TRANSACTION_IN_PROGRESS_STATE)
-          success_return_value
-        end
+        result = session.with_transaction(timeout_ms: 0) { success_return_value }
         expect(result).to eq(success_return_value)
       end
     end