[Refactoring] Use isAggregate function more
[Refactoring] Consider failed-semantic aggregates

Related to the end of (Struct|Class|Interface)Declaration::semantic.
fix Issue 8735 - ICE: Assertion failure: 't' on line 100 in file 'aliasthis.c'
Merge pull request #2762 from 9rnsr/fix8735

Issue 8735 - ICE: Assertion failure: 't' on line 100 in file 'aliasthis.c'