configs: Fix stat names after switchable changes

b6e0e72d9 changed the names of the switchable processor cores. This
change updates the stats after the nightlies failed.

Change-Id: If349ff07dea08ad3999e02ee95da389bab903b3e
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/62791
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

configs/example/gem5_library/x86-parsec-benchmarks.py

@@ -279,11 +279,11 @@ gem5stats = get_simstat(root)
 # We get the number of committed instructions from the timing
 # cores. We then sum and print them at the end.
 roi_insts = float(
-    gem5stats.to_json()["system"]["processor"]["cores2"]["core"][
+    gem5stats.to_json()["system"]["processor"]["switch0"]["core"][
         "exec_context.thread_0"
     ]["numInsts"]["value"]
 ) + float(
-    gem5stats.to_json()["system"]["processor"]["cores3"]["core"][
+    gem5stats.to_json()["system"]["processor"]["switch1"]["core"][
         "exec_context.thread_0"
     ]["numInsts"]["value"]
 )