Hide FunctionTemplateDecl's specializations folding set as implementation detail and introduce
FunctionTemplateDecl::findSpecialization.

Redeclarations of specializations will not cause the previous decl to be removed from the set,
the set will keep the canonical decl. findSpecialization will return the most recent redeclaration.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108834 91177308-0d34-0410-b5e6-96231b3b80d8
6 files changed