fix(test): close tester in custom_bc truncation describe afterEach

The third describe block created a PublicTxSimulationTester (owns
AvmSimulatorPool + CdbIpcServer) per test but only closed worldStateService
in afterEach, leaking the AVM pool and CDB server each iteration. Jest could
not exit after the suite completed and was killed at the 600s CI timeout.

Author: charlielye

yarn-project/simulator/src/public/public_tx_simulator/apps_tests/custom_bc.test.ts

@@ -113,6 +113,7 @@ describe('Public TX simulator apps tests: custom bytecodes truncation', () => {
   });
 
   afterEach(async () => {
+    await tester.close();
     await worldStateService.close();
   });