Fix failing thread pool test on low core count machines

Author: mark-vieira

server/src/test/java/org/elasticsearch/threadpool/UpdateThreadPoolSettingsTests.java

@@ -79,7 +79,11 @@ public void testWriteThreadPoolsMaxSize() throws InterruptedException {
     }
 
     private static int getExpectedThreadPoolSize(Settings settings, String name, int size) {
-        if (name.equals(ThreadPool.Names.WRITE) || name.equals(Names.SYSTEM_WRITE) || name.equals(Names.SYSTEM_CRITICAL_WRITE)) {
+        if (name.equals(ThreadPool.Names.WRITE)
+            || name.equals(Names.SYSTEM_WRITE)
+            || name.equals(Names.SYSTEM_CRITICAL_WRITE)
+            || name.equals(Names.WRITE_COORDINATION)
+            || name.equals(Names.SYSTEM_WRITE_COORDINATION)) {
             return Math.min(size, EsExecutors.allocatedProcessors(settings));
         } else {
             return size;