[utils] Update SmallVector lldb formatter for r337514

SmallVector was changed to store a begin and a size rather than a
begin and an end a while back. Update the formatter to look at the
correct members.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@346252 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed