fix memory leak in pass manager when adding an analysis pass that already existed...

fix memory leak in pass manager when adding an analysis pass that already existed. as pass manager takes ownership of the added passes, it has to delete the pass if it isnt added to the pass list
tweak the opt tool so that it doesnt access a Pass after the ownership was taken by the pass manager

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@58730 91177308-0d34-0410-b5e6-96231b3b80d8