Fixed a problem where the expression parser would
not find multiple functions with the same name but
different types.  Now we keep track of what types
we've already reported for a function and only elide
functions if we've already reported a conflicting
one.

Also added a test case.

<rdar://problem/11367837>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@180167 91177308-0d34-0410-b5e6-96231b3b80d8