Automatically do the equivalent of freeMachineCodeForFunction(F) when F is

Automatically do the equivalent of freeMachineCodeForFunction(F) when F is
being destroyed. This allows users to run global optimizations like globaldce
even after some functions have been jitted.

This patch also removes the Function* parameter to
JITEventListener::NotifyFreeingMachineCode() since it can cause that to be
called when the Function is partially destroyed. This change will be even more
helpful later when I think we'll want to allow machine code to actually outlive
its Function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@85182 91177308-0d34-0410-b5e6-96231b3b80d8