[Test][Isolated Region] Reduce memory usage in test_slurm_memory_based_scheduling

The changed line is running on c5.large, which has 4GB of physical memory, when running with 3GB of program, it failed in isolated region on RHEL8. Reduce the memory usage to 2GB to make the test pass. ParallelCluster test shouldn't check too strictly about memory usage because it is managed by operating systems.

Author: hanwen-cluster

tests/integration-tests/tests/schedulers/test_slurm.py

@@ -2594,7 +2594,7 @@ def _test_slurm_behavior_when_updating_schedulable_memory_with_already_running_j
         submit_command_args={
             "nodes": 1,
             "slots": 1,
-            "command": "srun ./a.out 2800000000 390",
+            "command": "srun ./a.out 2000000000 390",
             "other_options": "-w queue1-st-ondemand1-i1-1",
             "raise_on_error": False,
         }