stdlib: Update LoopPointRestore to take singular region_id

This change has been introduced as we only restore to one checkpoint at
a time. The change updates LoopPointRestore to take a sigular region_id
and use it to generate the LoopPpoint from the LoopPoint JSON file.

Change-Id: I0e88d5ba03b164bdd5da098397f44e16af591134
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/67492
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
1 file changed