Fix intermittent test failure in SessionCacheTwoServerTest

[jjiwooLim]

Fix intermittent test failure due to race condition.
Added sync parameter to the sessionPut call to force synchronous write to cache

This change does not affect the functionality of the test as the test is just checking the configuration of httpSessionCahce-writeContents

• I have considered the risk of behavior change or other zero migration impact (https://github.com/OpenLiberty/open-liberty/wiki/Behavior-Changes).
• If this PR fixes an Issue, the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN" (verify release bug label if applicable: https://github.com/OpenLiberty/open-liberty/wiki/Open-Liberty-Conventions).
• If this PR resolves an external Known Issue (including APARS), the description includes "Fixes #FILLMEIN" or "Resolves #FILLMEIN".

[jjiwooLim]

!build (view Open Liberty Personal Build - ✅ completed successfully!)

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[LibbyBot]

Code analysis and actions

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[jjiwooLim]

Build looks good, removed the copyrights header

[pnicolucci]

We can't remove the copyright header, my comment was specific to two things:

1. Just remove the Contributors section as it is no longer necessary for example:

/*******************************************************************************
 * Copyright (c) 2018, 2022 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-2.0/
 * 
 * SPDX-License-Identifier: EPL-2.0
 *******************************************************************************/

2. Update the copyright header date range to include 2025 if you agree that this is a significant enough change.

Also it would be good for someone from the session team to review this.