Fixed flaky ssl fullMethod test (#7896)

* Fixed flaky test

jetty-server/src/test/java/org/eclipse/jetty/server/HttpServerTestBase.java

@@ -209,8 +209,16 @@ public abstract class HttpServerTestBase extends HttpServerTestFixture
             byte[] buffer = new byte[64 * 1024];
             Arrays.fill(buffer, (byte)'A');
 
-            os.write(buffer);
-            os.flush();
+            try
+            {
+                os.write(buffer);
+                os.flush();
+            }
+            catch (Exception e)
+            {
+                if (LOG.isDebugEnabled())
+                    LOG.debug("write exception", e);
+            }
 
             // Read the response.
             String response = readResponse(client);