Integrated: 8255852: Shenandoah: Fix incorrect copyright header in new files added by 8254315

[Roman Kennke]

I apparently pushed files with broken copyright:

src/hotspot/share/gc/shenandoah/shenandoahMarkBitMap.cpp
src/hotspot/share/gc/shenandoah/shenandoahMarkBitMap.hpp
src/hotspot/share/gc/shenandoah/shenandoahMarkBitMap.inline.hpp
src/hotspot/share/gc/shenandoah/shenandoahReferenceProcessor.cpp
src/hotspot/share/gc/shenandoah/shenandoahReferenceProcessor.hpp

They are missing the line:

* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 

Testing: build (x86_64)

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Commit messages:
 - 8255852: Shenandoah: Fix incorrect copyright header in new files added by 8254315

Changes: https://git.openjdk.java.net/jdk/pull/1042/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=1042&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8255852
  Stats: 5 lines in 5 files changed: 5 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/1042.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/1042/head:pull/1042

PR: https://git.openjdk.java.net/jdk/pull/1042