Fix race condition in getXOpaqueId in tests

Due to a race condition between isClosed and getHeader it is possible
that getXOpaqueId can throw an IllegalStateException.
This only  occurs when run with multiple tests on the same JVM. This
value is not to be asserted in these tests. Only when running in
isolation in its own JVM.
This won't happen in production as we only expect one ThreadContext per
Node (jvm)

closes elastic#45443

Author: pgomulka

server/src/main/java/org/elasticsearch/common/logging/DeprecationLogger.java

@@ -261,12 +261,19 @@ public Void run() {
     }
 
     public String getXOpaqueId(Set<ThreadContext> threadContexts) {
-        return threadContexts.stream()
-                             .filter(t -> t.isClosed() == false)
-                             .filter(t -> t.getHeader(Task.X_OPAQUE_ID) != null)
-                             .findFirst()
-                             .map(t -> t.getHeader(Task.X_OPAQUE_ID))
-                             .orElse("");
+        for (ThreadContext threadContext : threadContexts) {
+            try {
+                if (threadContext.isClosed() == false) {
+                    String header = threadContext.getHeader(Task.X_OPAQUE_ID);
+                    if (header != null) {
+                        return header;
+                    }
+                }
+            } catch (IllegalStateException e) {
+                // ignore exception as this is due to a race condition  between isClosed and getHeader
+            }
+        }
+        return "";
     }
 
     /**