Print debugger logs to stderr on Flex Java, so that they will show up on Cloud

Logging.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=155415372

Author: emrekultursay

src/agent/format-env-appengine-vm.sh

@@ -36,7 +36,7 @@ CDBG_ROOT="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
 
 ARGS="-agentpath:${CDBG_ROOT}/cdbg_java_agent.so="
 ARGS+="--log_dir=/var/log/app_engine"
-ARGS+=",--logtostderr=false"
+ARGS+=",--alsologtostderr=true"
 
 # When using Jetty/Tomcat images, the debugger should also read the
 # WEB-INF/classes and WEB-INF/lib directories. When using the OpenJDK