increase middlemanager heap server size in tests (#14345)

diff --git a/integration-tests/docker/environment-configs/middlemanager b/integration-tests/docker/environment-configs/middlemanager
index be50c66..25ac396 100644
--- a/integration-tests/docker/environment-configs/middlemanager
+++ b/integration-tests/docker/environment-configs/middlemanager
@@ -21,7 +21,7 @@
 DRUID_LOG_PATH=/shared/logs/middlemanager.log
 
 # JAVA OPTS
-SERVICE_DRUID_JAVA_OPTS=-server -Xmx64m -Xms64m -XX:+UseG1GC -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5008
+SERVICE_DRUID_JAVA_OPTS=-server -Xmx128m -Xms64m -XX:+UseG1GC -agentlib:jdwp=transport=dt_socket,server=y,suspend=n,address=5008
 
 # Druid configs
 druid_host=druid-middlemanager