[ASTImporter] Fix redecl failures of Class and ClassTemplate
Summary:
Redecl chains of classes and class templates are not handled well
currently. We want to handle them similarly to functions, i.e. try to
keep the structure of the original AST as much as possible. The aim is
to not squash a prototype with a definition, rather we create both and
put them in a redecl chain.
Reviewers: a_sidorin, shafik, a.sidorin
Subscribers: rnkovacs, dkrupp, Szelethus, gamesh411, jdoerfert, cfe-commits
Tags: #clang
Differential Revision: https://reviews.llvm.org/D58502
llvm-svn: 355390