sim: Use ref constructor of MemberEventWrapper everywhere

Change-Id: I77989aa7318142634c771c558293138e7b1e8e51
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67657
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
9 files changed