Use the 'count' attribute instead of the 'upper_bound' attribute.

If we have a type 'int a[1]' and a type 'int b[0]', the generated DWARF is the
same for both of them because we use the 'upper_bound' attribute. Instead use
the 'count' attrbute, which gives the correct number of elements in the array.
<rdar://problem/12566646>


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@167806 91177308-0d34-0410-b5e6-96231b3b80d8