Follow up to #9927 (#9930)

`System.getProperty` does not return `null`, it returns `"null"`
:facepalm:.
I broke the internet, sorry.

Author: hubertp

lib/scala/runtime-version-manager/src/main/scala/org/enso/runtimeversionmanager/runner/JVMSettings.scala

@@ -59,7 +59,9 @@ object JVMSettings {
 
   private def jvmOptionIfSet(name: String): Option[(String, String)] = {
     val propertyValue = System.getProperty(name)
-    Option(propertyValue).map((name, _))
+    if (propertyValue != null && !propertyValue.isEmpty)
+      Some((name, propertyValue))
+    else None
   }
 
 }