Pass ES_JAVA_OPTS to JVM for plugins script

This commit adds support for ES_JAVA_OPTS to the elasticsearch-plugin
script.

Relates #18140

distribution/src/main/resources/bin/elasticsearch-plugin

@@ -110,4 +110,4 @@ fi
 HOSTNAME=`hostname | cut -d. -f1`
 export HOSTNAME
 
-eval "\"$JAVA\"" -client -Delasticsearch -Des.path.home="\"$ES_HOME\"" $properties -cp "\"$ES_HOME/lib/*\"" org.elasticsearch.plugins.PluginCli $args
+eval "\"$JAVA\"" "$ES_JAVA_OPTS" -client -Delasticsearch -Des.path.home="\"$ES_HOME\"" $properties -cp "\"$ES_HOME/lib/*\"" org.elasticsearch.plugins.PluginCli $args

distribution/src/main/resources/bin/elasticsearch-plugin.bat

@@ -48,7 +48,7 @@ GOTO loop
 
 SET HOSTNAME=%COMPUTERNAME%
 
-"%JAVA_HOME%\bin\java" -client -Des.path.home="%ES_HOME%" !properties! -cp "%ES_HOME%/lib/*;" "org.elasticsearch.plugins.PluginCli" !args!
+"%JAVA_HOME%\bin\java" %ES_JAVA_OPTS% -client -Des.path.home="%ES_HOME%" !properties! -cp "%ES_HOME%/lib/*;" "org.elasticsearch.plugins.PluginCli" !args!
 goto finally
 
 

qa/vagrant/src/test/resources/packaging/scripts/module_and_plugin_test_cases.bash

@@ -476,3 +476,15 @@ fi
     # restore JAVA_HOME
     export JAVA_HOME=$java_home
 }
+
+@test "[$GROUP] test ES_JAVA_OPTS" {
+    # preserve ES_JAVA_OPTS
+    local es_java_opts=$ES_JAVA_OPTS
+
+    export ES_JAVA_OPTS="-XX:+PrintFlagsFinal"
+    # this will fail if ES_JAVA_OPTS is not passed through
+    "$ESHOME/bin/elasticsearch-plugin" list | grep MaxHeapSize
+
+    # restore ES_JAVA_OPTS
+    export ES_JAVA_OPTS=$es_java_opts
+}