Fix an instantiation bug with nested generic lambdas and conversion to fptrs.

Fix an instantiation bug with nested generic lambdas and conversion to fptrs.

This patch fixes the typelocs of the conversion-operator and the conversion-operator-name and adds the parameters of the call operator to the FunctionProtoTypeLoc of the respective entities. Thus, when the template declarations (conversion operators) undergo deduction and instantiation/transformation/substitution - they add themselves to the local instantiation scope if needed.

This patch supports the following:

auto L = [](auto b) {
  return [](auto a) ->decltype(a) { return a; };
};
int (*fp)(int) = L(8);

Richard LGTM'd this patch: http://llvm-reviews.chandlerc.com/D1831

Thanks!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@193294 91177308-0d34-0410-b5e6-96231b3b80d8