Fix Jetty start script (#2958)

Script broken by inlined comment in multi-line command with backslash.

Refactored into comment-safe format.

Author: weiminyu

jetty/start.sh

@@ -27,10 +27,13 @@ case "${CONTAINER_NAME}" in
   "frontend"|"console")
   PROFILER_ARGS="-agentpath:/opt/cprof/profiler_java_agent.so=-cprof_service=${CONTAINER_NAME},-cprof_enable_heap_sampling=true"
 esac
-java $PROFILER_ARGS \
-    # Allocate bigger than default fraction of available memory to the application, as it's running in a (single-purposed) container.
-    -XX:InitialRAMPercentage=50.0 \
-    -XX:MaxRAMPercentage=50.0 \
-    -Dgoogle.registry.environment=${env} \
-    -Djava.util.logging.config.file=/logging.properties \
+JVM_OPTS=(
+    # Allocate bigger than default fraction of available memory to the
+    # application, as it's running in a (single-purposed) container.
+    -XX:InitialRAMPercentage=50.0
+    -XX:MaxRAMPercentage=50.0
+    -Dgoogle.registry.environment="${env}"
+    -Djava.util.logging.config.file=/logging.properties
     -jar /usr/local/jetty/start.jar
+)
+java $PROFILER_ARGS "${JVM_OPTS[@]}"