tests: Increase Kokoro test timeout to 7 hours

Change-Id: I5a334124cc14d7db3a6227981ed46ae0cc80e558
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/54824
Reviewed-by: Bobby Bruce <bbruce@ucdavis.edu>
Maintainer: Bobby Bruce <bbruce@ucdavis.edu>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/tests/jenkins/presubmit.cfg b/tests/jenkins/presubmit.cfg
index a356c76..ef25969 100644
--- a/tests/jenkins/presubmit.cfg
+++ b/tests/jenkins/presubmit.cfg
@@ -3,4 +3,4 @@
 # Location of the continuous batch script in repository.
 build_file: "jenkins-gem5-prod/tests/jenkins/presubmit.sh"
 
-timeout_mins: 360 # 6 hours
+timeout_mins: 420 # 7 hours