Remove this code as it is currently completely broken and unmaintained.

Remove this code as it is currently completely broken and unmaintained.
If needed, this can be resurrected from CVS.

Note that several of the interfaces (e.g. the IPModRef ones) are supersumed
by generic AliasAnalysis interfaces that have been written since this code
was developed (and they are not DSA specific).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19864 91177308-0d34-0410-b5e6-96231b3b80d8