[NFC][ArgumentPromotion] Clear FAM cached results of erased function.

Not doing it here can lead to subtle bugs - the analysis results are
associated by the Function object's address. Nothing stops the memory
allocator from allocating new functions at the same address.

llvm/lib/Transforms/IPO/ArgumentPromotion.cpp

@@ -1052,6 +1052,7 @@ PreservedAnalyses ArgumentPromotionPass::run(LazyCallGraph::SCC &C,
       // swaps out the particular function mapped to a particular node in the
       // graph.
       C.getOuterRefSCC().replaceNodeFunction(N, *NewF);
+      FAM.clear(OldF, OldF.getName());
       OldF.eraseFromParent();
     }