Fix race condition in NodeTestTask (#5427)

Fixed by making field `parentContext` volatile.

Issue: #5408

Signed-off-by: Jakob Villumsen <villumsen@google.com>

Author: jaschdoc

documentation/modules/ROOT/partials/release-notes/release-notes-5.14.4.adoc

@@ -13,8 +13,10 @@ repository on GitHub.
 [[v5.14.4-junit-platform]]
 === JUnit Platform
 
-No changes.
+[[v5.14.4-junit-platform-bug-fixes]]
+==== Bug Fixes
 
+* A race condition in `NodeTestTask.parentContext` has been fixed.
 
 [[v5.14.4-junit-jupiter]]
 === JUnit Jupiter

junit-platform-engine/src/main/java/org/junit/platform/engine/support/hierarchical/NodeTestTask.java

@@ -51,7 +51,7 @@ class NodeTestTask<C extends EngineExecutionContext> implements TestTask {
 	private final Node<C> node;
 	private final Runnable finalizer;
 
-	private C parentContext;
+	private volatile C parentContext;
 	private C context;
 
 	private SkipResult skipResult;