[vala] (10 commits) ...tests: Add "generics reference transfer" test to increase coverage

[Rico Tzschichholz <ricotz src gnome org>]

Summary of changes:

  38d61fb... vala: Properly check GLib.Object naming convention for prop (*)
  edc0b53... codegen: Apply gconstpointer to gpointer cast to GenericTyp (*)
  7641f50... codegen: Fix access to captured generics in async method of (*)
  c2a9ded... codegen: Add get_generic_type_expression() and handle Gener (*)
  b8be96c... Make TypeParameter a TypeSymbol to resolve functions with a (*)
  58675b6... codegen: Unify handling of GenericType arguments/parameters (*)
  b165d68... codegen: Use if-clause for is_in_destructor() condition to  (*)
  6f30d21... codegen: More use of get_variable_cexpression() (*)
  376df8b... tests: Extend "finally block execution" test to increase co (*)
  f1d8635... tests: Add "generics reference transfer" test to increase c (*)

(*) This commit already existed in another branch; no separate mail sent