[Refactoring] Convert AggregateDeclaration::handle to handleType()
More better fix for issue 11075 to reproduce semantic3 errors in already failed template instance
fix Issue 12378 - Compiler accepts any syntactically-valid code inside double-nested map predicate
Merge pull request #3383 from 9rnsr/fix12378

Issue 12378 - Compiler accepts any syntactically-valid code inside double-nested map predicate