When deciding how to parse "= something" as part of a member

When deciding how to parse "= something" as part of a member
declaration, determine whether the declaration will end up declaring a
function using semantic criteria (e.g., it will have function type)
rather than purely syntactic criteria (e.g., it has the form of a
function declarator). Fixes <rdar://problem/9670557>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@133854 91177308-0d34-0410-b5e6-96231b3b80d8