Previously, `isScopeAffectingInstructionDead` determined that
an otherwise satisfactory `load` was not dead if it was a `load [take]`.
The immediate effect was that dead `load [take]`s were not deleted. The
downstream effect was that otherwise dead graphs of instructions would
not be deleted. This was especially a problem for OSLogOptimization
which deletes a great deal of code.
Here, the InstructionDeleter is taught to compensate for the deletion of
such `load [take]` by inserting `destroy_addr`s in their stead.
rdar://117011668
