Use a scheme closer to that of GNU as when deciding the type of a
symbol with multiple .type declarations.

Differential Revision: http://llvm-reviews.chandlerc.com/D607

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@179184 91177308-0d34-0410-b5e6-96231b3b80d8