Fix initialization and re-computation of expirationTimestamp in Http2ClientConnectionImpl

Closes #5865

Author: ahus1

vertx-core/src/main/java/io/vertx/core/http/impl/http2/codec/Http2ClientConnectionImpl.java

@@ -62,6 +62,8 @@ public class Http2ClientConnectionImpl extends Http2ConnectionImpl implements Ht
     this.authority = authority;
     this.lifetimeEvictionTimestamp = maxLifetime > 0 ? System.currentTimeMillis() + maxLifetime : Long.MAX_VALUE;
     this.handler = connHandler;
+    // Ensure that the expirationTimestamp is initialized
+    recycle();
   }
 
   @Override
@@ -199,8 +201,9 @@ private void recycle() {
 
   @Override
   void onStreamClosed(Http2Stream s) {
-    super.onStreamClosed(s);
+    // Prepare this connection for returning as onStreamClosed() will return it to the pool.
     recycle();
+    super.onStreamClosed(s);
   }
 
   @Override