Fix regression following fix for 69967

The two special headers get added during commit.
BZ70000

Author: rmaucher

java/org/apache/catalina/connector/Response.java

@@ -797,11 +797,13 @@ public Collection<String> getHeaderNames() {
         for (int i = 0; i < n; i++) {
             result.add(headers.getName(i).toString());
         }
-        if (getCoyoteResponse().getContentType() != null) {
-            result.add("Content-Type");
-        }
-        if (getCoyoteResponse().getContentLengthLong() != -1) {
-            result.add("Content-Length");
+        if (!getCoyoteResponse().isCommitted()) {
+            if (getCoyoteResponse().getContentType() != null) {
+                result.add("Content-Type");
+            }
+            if (getCoyoteResponse().getContentLengthLong() != -1) {
+                result.add("Content-Length");
+            }
         }
         return result;
     }

webapps/docs/changelog.xml

@@ -124,6 +124,10 @@
         Align the escaping in <code>ExtendedAccessLogValve</code> with the other
         <code>AccessLogValve</code> implementations. (markt)
       </fix>
+      <fix>
+        <bug>70000</bug>: fix duplication of special headers in the response
+        after commit, following fix for <bug>69967</bug>. (remm)
+      </fix>
     </changelog>
   </subsection>
   <subsection name="Coyote">