Fix ITs for Maven 4 compat

[Bukama]

Changes extracted in own PR, as requested in #1311.

Local build with Maven 3.9.16 and admin rights (due this symlink case)

D:\Github\Maven\maven-assembly-plugin>mvn clean verify -Prun-its -V
Apache Maven 3.9.16 (2bdd9fddda4b155ebf8000e807eb73fd829a51d5)
Maven home: C:\apache-maven-3.9.16
Java version: 25.0.2, vendor: Azul Systems, Inc., runtime: C:\Program Files\Zulu\zulu-25
Default locale: de_DE, platform encoding: UTF-8
OS name: "windows 11", version: "10.0", arch: "amd64", family: "windows"
[INFO] Scanning for projects...


[INFO] -------------------------------------------------
[INFO] Build Summary:
[INFO]   Passed: 148, Failed: 0, Errors: 0, Skipped: 2
[INFO] -------------------------------------------------
[WARNING] The following builds were skipped:
[WARNING] *  projects\bugs\massembly-731\pom.xml
[WARNING] *  projects\file-modes\file-set-fileMode\pom.xml
[INFO] -------------------------------------------------
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time:  08:19 min
[INFO] Finished at: 2026-06-14T14:18:03+02:00
[INFO] ------------------------------------------------------------------------

Local build with Maven 4.0.0-SNAPSHOT and admin rights (due this symlink case)

D:\Github\Maven\maven-assembly-plugin>mvn --version
Apache Maven 4.0.0-SNAPSHOT (8bedea9479918bdac71455635f0c51a2b5730f05)
Maven home: C:\apache-maven-4.0.x-self
Java version: 25.0.2, vendor: Azul Systems, Inc., runtime: C:\Program Files\Zulu\zulu-25
Default locale: de_DE, platform encoding: UTF-8, time zone: Europe/Berlin
OS name: "windows 11", version: "10.0", arch: "amd64", family: "winnt"


[INFO] Build Summary:
[INFO]   Passed: 148, Failed: 0, Errors: 0, Skipped: 2
[INFO] -------------------------------------------------
[WARNING] The following builds were skipped:
[WARNING] *  projects\bugs\massembly-731\pom.xml
[WARNING] *  projects\file-modes\file-set-fileMode\pom.xml
[INFO] -------------------------------------------------
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] --------------------------------------------------------------------------------------------------------------------------
[INFO] Total time:  10:53 min
[INFO] Finished at: 2026-06-14T16:00:39+02:00
[INFO] --------------------------------------------------------------------------------------------------------------------------

Interesting that Maven 4 is almost three minutes slower.