[Groovy] Prevent NPE for mark occurrences #11794

Job	Run time
Build Clusters on JDK 17	10m 0s
Build Clusters on JDK 21	8m 10s
Build Clusters on JDK 24-ea	7m 31s
NetBeans on nb-javac	0s
Build-System / Misc Tests on Linux/JDK 17	14m 1s
CV on ubuntu-latest/JDK 17	9m 26s
Check Paperwork on Linux/JDK 17	12m 52s
IDE Modules on Linux/JDK 17	18m 50s
CV on macos-latest/JDK 17	16m 53s
CV on windows-latest/JDK 17	14m 16s
Build ${{ matrix.config }} from src.zip on JDK ${{ matrix.java }}	0s
CV on ubuntu-latest/JDK 23	8m 35s
Build-Tools on Linux/JDK ${{ matrix.java }}	0s
Platform Modules batch1 on Linux/JDK ${{ matrix.java }} (some on 8)	0s
Platform Modules batch2 on Linux/JDK ${{ matrix.java }}	0s
Java Modules on Linux/JDK ${{ matrix.java }}	0s
Java Hints ${{ matrix.config }} on Linux/JDK ${{ matrix.java }}	0s
Java Debugger tests on Linux/JDK ${{ matrix.java }}	0s
Profiler on Linux/JDK ${{ matrix.java }}	0s
Web Modules on Linux/JDK ${{ matrix.java }}	0s
Groovy on Linux/JDK 17	10m 38s
JavaFX on Linux/JDK ${{ matrix.java }}	0s
Enterprise on Linux/JDK ${{ matrix.java }}	0s
Rust on Linux/JDK ${{ matrix.java }}	0s
LSP tests on Linux/JDK ${{ matrix.java }}	0s
DB Tests with MySQL on Linux/JDK ${{ matrix.java }}	0s
Versioning Modules on Linux/JDK ${{ matrix.java }}	0s
PHP on ${{ matrix.os }}/JDK ${{ matrix.java }}	0s
GraalVM ${{ matrix.graal }} Tests	0s
VSCode Extension Tests on JDK ${{ matrix.java }}	0s
Cleanup Workflow Artifacts	1m 42s
	2h 12m 54s

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