mem-ruby: Do not change blocked msg enqueue info
mem-ruby: Do not change blocked msg enqueue info

Updating the message counter and enqueue times when adding blocked
messages back to the queue does not make a lot of sense since these
messages are not new arrivals.
More importantly, this may lead to starvation. See the scenario below:

1) Request A for a blocked line X arrives
2) A is handled; X is blocked so A is stalled
3) Request B for X arrives; Reponse for X arrives
4) Response is handled; X unblocked; A added back to the request queue
5) B is handled ahead of A (since A's arrival was updated);
   X may become blocked again

If new requests keep comming for X, A may will be stalled forever.

Change-Id: Icad79f3f716a870e91cb3455437b8b3c35f130ac
Signed-off-by: Tiago Muck <02f879f33eea3aaf6781160757a59709a6f01bed@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18412
Tested-by: kokoro <2ac7b1f3fa578934c95181d4272be0d3bca00121@google.com>
Reviewed-by: Jason Lowe-Power <68c46a606457643eab92053c1c05574abb26f861@lowepower.com>
Reviewed-by: Matthew Poremba <f1eb50f3368ce197c52b19f7fdb5aa7a278f15fd@amd.com>
Maintainer: Jason Lowe-Power <68c46a606457643eab92053c1c05574abb26f861@lowepower.com>

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