Make sure --source-config target is decoded

Author: jisedlac

visualvm/gotosource/src/org/graalvm/visualvm/gotosource/arguments/SourceConfigArgument.java

@@ -60,6 +60,7 @@ private static void setValue(String value) throws CommandException {
             SourceRootsArgument.setValue(null);
             SourceViewerArgument.setValue(null);
         } else {
+            value = SourceArguments.decode(value);
             try (InputStreamReader isr = new InputStreamReader(new FileInputStream(value), "UTF-8")) { // NOI18N
                 Properties props = new Properties();
                 props.load(isr);