Update Java in performance pipeline (#1086)

Update performance pipeline to use Java 26 and
make it the only option.

Signed-off-by: Kostas Tsiounis <kostas.tsiounis@ibm.com>

Author: KostasTsiounis

Jenkinsfile

@@ -325,7 +325,7 @@ pipeline {
             Typically this will use https://github.com/IBM/OpenJCEPlus')
         string(name: 'OPENJCEPLUS_BRANCH', defaultValue: '', description: '\
             The OpenJCEPlus branch to be used. When not specified this will default to the branch scanned by this multibranch pipeline.')
-        choice(name: 'JAVA_VERSION', choices: ['26', '25', '24', '23', '22', '21', '17', '11'], description: '\
+        string(name: 'JAVA_VERSION', defaultValue: '26', description: '\
             Specify the Java version your branch uses to build.')
         string(name: 'JAVA_RELEASE', defaultValue: '', description: '\
             Indicate a specific Java release that you want to use to build your branch.<br> \

JenkinsfilePerformance

@@ -1,5 +1,5 @@
 /*
- * Copyright IBM Corp. 2025
+ * Copyright IBM Corp. 2025, 2026
  *
  * This code is free software; you can redistribute it and/or modify it
  * under the terms provided by IBM in the LICENSE file that accompanied
@@ -215,7 +215,9 @@ def run(platform) {
                         }
                     }
 
-                    externalLibrary.getJava(hardware, software)
+                    withCredentials([usernamePassword(credentialsId: '7c1c2c28-650f-49e0-afd1-ca6b60479546', passwordVariable: 'ARTIFACTORY_PASSWORD', usernameVariable: 'ARTIFACTORY_USERNAME')]) {
+                        externalLibrary.getJava(hardware, software)
+                    }
                     echo "Java fetched"
                     externalLibrary.getBinaries(hardware, software)
                     echo "Binaries fetched"
@@ -301,7 +303,7 @@ pipeline {
             Typically this will use https://github.com/IBM/OpenJCEPlus')
         string(name: 'OPENJCEPLUS_BRANCH', defaultValue: '', description: '\
             The OpenJCEPlus branch to be used. When not specified this will default to the branch scanned by this multibranch pipeline.')
-        choice(name: 'JAVA_VERSION', choices: ['25', '24', '23', '22', '21', '17', '11'], description: '\
+        string(name: 'JAVA_VERSION', defaultValue: '26', description: '\
             Specify the Java version your branch uses to build.')
         string(name: 'JAVA_RELEASE', defaultValue: '', description: '\
             Indicate a specific Java release that you want to use to build your branch.<br> \