[jdk21u-dev] RFR: 8324681: Replace NULL with nullptr in HotSpot jtreg test native code files

[Goetz Lindenmaier]

I would like to backport this change to keep maintaining the tests more easy.
It will make later backports clean, saving tedious reviews.

Despite the many touched files, only four files do not patch clean:

test/hotspot/jtreg/serviceability/jvmti/GetClassFields/FilteredFields/libFilteredFieldsTest.cpp
Was added by https://bugs.openjdk.org/browse/JDK-8318626: GetClassFields does not filter out ConstantPool.constantPoolOop field
Omitted.

patching file test/hotspot/jtreg/vmTestbase/nsk/jvmti/unit/functions/rawmonitor/rawmonitor.cpp
Later change already backported.  Resolved Copyright.


|+++ b/test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/unnamed/libLinkerInvokerUnnamed.cpp
Was moved to other location by "https://bugs.openjdk.org/browse/JDK-8312522: Implementation of Foreign Function & Memory API".
Applied hunk to test/jdk/java/foreign/enablenativeaccess/org/openjdk/foreigntest/libLinkerInvokerUnnamed.cpp


patching file test/jdk/java/foreign/enablenativeaccess/panama_module/org/openjdk/foreigntest/libLinkerInvokerModule.cpp
Not clean because of "https://bugs.openjdk.org/browse/JDK-8312522: Implementation of Foreign Function & Memory API" missing in 21.
 Resolved Copyright.

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Commit messages:
 - Resolved files
 - Backport a6bdee48f39993128d8095d40ab417f0102af0f4

Changes: https://git.openjdk.org/jdk21u-dev/pull/1772/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1772&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324681
  Stats: 8214 lines in 749 files changed: 0 ins; 7 del; 8207 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1772.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1772/head:pull/1772

PR: https://git.openjdk.org/jdk21u-dev/pull/1772