Fix more lambda patterns

[lucic71]

1. Fix defaultable lambdas that contain static locals
2. Translate static invoker of lambda (when passing the lambda to a template)
3. Fix name generator for lambdas
   i. We need the same ASTNameGenerator for the entire lifetime of the converter, otherwise we get name clashes between mangled templates that receive lambdas
4. Fix redeclarations in IsUserDefinedDecl