tests: Removing Atomic CPU with Ruby tests

test_kvm_fork_run.py and test_kvm_cpu_switch.py both contained tests
which attempted to run a Ruby cache with an Atomic CPU. This is not
permitted. As such these tests have been removed.

Change-Id: I7996bda6313f59f76d7f9b73bef8351d72547481
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/52384
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

tests/gem5/kvm-fork-tests/test_kvm_fork_run.py

@@ -117,12 +117,6 @@ test_kvm_fork_run(
 
 ### The long (nightly) tests ####
 
-test_kvm_fork_run(
-    cpu="atomic",
-    num_cpus=1,
-    mem_system="mesi_two_level",
-    length=constants.long_tag,
-)
 test_kvm_fork_run(
     cpu="timing",
     num_cpus=1,

tests/gem5/kvm-switch-tests/test_kvm_cpu_switch.py

@@ -115,12 +115,6 @@ test_kvm_switch(
 
 ### The long (nightly) tests ####
 
-test_kvm_switch(
-    cpu="atomic",
-    num_cpus=1,
-    mem_system="mesi_two_level",
-    length=constants.long_tag,
-)
 test_kvm_switch(
     cpu="timing",
     num_cpus=1,