GEODE: Decrease number of test containers for Distributed Test

The number of test containers needs to be decreased from 10 to 8,
as the current VM 24C/128GB can't handle the load.

Change-Id: I740ecd32a4105bbe473ff56956ed29c68b88b0be
diff --git a/jjb/geode/apache-geode-test/apache-geode-distributed-test.yaml b/jjb/geode/apache-geode-test/apache-geode-distributed-test.yaml
index 9168637..93c6bb5 100644
--- a/jjb/geode/apache-geode-test/apache-geode-distributed-test.yaml
+++ b/jjb/geode/apache-geode-test/apache-geode-distributed-test.yaml
@@ -31,7 +31,7 @@
     java-test-version: '11'
     parallel-gradle: 'true'
     parallel-dunit: 'true'
-    dunit-parallel-forks: '12'
+    dunit-parallel-forks: '10'
 
     jobs:
       - 'apache-geode-{test-type}Test-jdk{java-test-version}'