Link to SYSTEM_JAVA_HOME on windows

We don't always have java home defined in packaging tests, as we want to
use the bundled jdk most of the time. This commit fixes the java home
with special characters test to link to SYSTEM_JAVA_HOME on windows.

closes elastic#40797

qa/vagrant/src/main/java/org/elasticsearch/packaging/test/ArchiveTestCase.java

@@ -203,7 +203,7 @@ public void test53JavaHomeWithSpecialCharacters() throws Exception {
             final Shell sh = new Shell();
             try {
                 // once windows 2012 is no longer supported and powershell 5.0 is always available we can change this command
-                sh.run("cmd /c mklink /D 'C:\\Program Files (x86)\\java' $Env:JAVA_HOME");
+                sh.run("cmd /c mklink /D 'C:\\Program Files (x86)\\java' $Env:SYSTEM_JAVA_HOME");
 
                 sh.getEnv().put("JAVA_HOME", "C:\\Program Files (x86)\\java");