FISH-6606 use temporary filename only while saving the uploaded file

Upgrade of common-upload probably changed the behaviour of saving file,
now it fails if the target file already exists. Now, we use only the
filename.
The temp file is still created as Java always creates it, it is
deleted before the uploaded file is written.

appserver/admingui/core/src/main/java/org/glassfish/admingui/handlers/WoodstockHandler.java

@@ -37,6 +37,7 @@
  * only if the new code is made subject to such option by the copyright
  * holder.
  */
+// Portions Copyright [2022] Payara Foundation and/or its affiliates
 
 /*
  * CommonHandlers.java
@@ -181,11 +182,12 @@ public static void uploadFileToTempDir(HandlerContext handlerCtx) {
                     prefix = prefix + new SecureRandom().nextInt(100000);
                 }
                 tmpFile = File.createTempFile(prefix, suffix);
-                FileUtils.deleteOnExit(tmpFile);
+                tmpFile.delete(); // remove the file as uploader fails, if it exists
                 if (logger.isLoggable(Level.FINE)) {
                     logger.fine(GuiUtil.getCommonMessage("log.writeToTmpFile"));
                 }
                 uploadedFile.write(tmpFile);
+                FileUtils.deleteOnExit(tmpFile);
                 if (logger.isLoggable(Level.FINE)) {
                     logger.fine(GuiUtil.getCommonMessage("log.afterWriteToTmpFile"));
                 }