Mangler: Lift shouldMangleDeclName predicate out of CXXNameMangler::mangle.
 - Sometimes we have to mangle things we wouldn't normally (e.g., because they appear in a template expression).

 - This also tidies up the predicate to be more obvious what is getting mangled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@89555 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed