8234408: Improve TLS session handling

Reviewed-by: ascarpino, jjiang, ahgross, ssahoo, mullan

src/java.base/share/classes/sun/security/ssl/TransportContext.java

@@ -130,7 +130,7 @@ final class TransportContext implements ConnectionContext {
         this.isUnsureMode = isUnsureMode;
 
         // initial security parameters
-        this.conSession = SSLSessionImpl.nullSession;
+        this.conSession = new SSLSessionImpl();
         this.protocolVersion = this.sslConfig.maximumProtocolVersion;
         this.clientVerifyData = emptyByteArray;
         this.serverVerifyData = emptyByteArray;