When a full backup operation times out, resources are cleaned up
including closing and nullifying pipes. However FullRestoreEngine.restoreOneFile()
doesn't stop execution and can access the pipes causing RuntimeException.
This CL adds a flag to show whether the operation has timed out and
checks it before accessing the pipes.
Bug: 126244736
Test: 1) atest RunBackupFrameworksServicesRoboTests
2) atest CtsBackupTestCases
3) atest CtsBackupHostTestCases
4) atest GtsBackupTestCases
5) atest GtsBackupHostTestCases
6) Manual: Test full backup/restore flow using Flipboard app
Change-Id: If400142a6fceaa4065409774bbff1cad8b4c6163