AIDEGen: Increase coverage of aidegen_main

Increase the code coverage of aidegen_main to 92%.

Bug: 152276736

Test: 1. $ sh ./run_test.sh
      2. The test coverage of aidegen_main is 92%
Change-Id: I4f9a9add9d8f4be54483b65529542c686222a796
1 file changed