Reinstantiate old/bad deduplication logic that was removed in r315279.

Reinstantiate old/bad deduplication logic that was removed in r315279.

While this shouldn't be necessary anymore, we have cases where we run
into the assertion below, i.e. cases with two non-fragment entries for the
same variable at different frame indices.

This should be fixed, but for now, we should revert to a version that
does not trigger asserts.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315576 91177308-0d34-0410-b5e6-96231b3b80d8