Is there a way to hide <l internal calls>? I think its unnecessary repeated annoying remainder taking space.

"ambiguous" or not, its a user to decide. If users don't want to see it then let them, don't enforce it.

Please follow the related request on YouTrack: https://youtrack.jetbrains.com/issue/IDEA-188173

Just right click that line and click "fold line like this".
One console will open ,there you just remove that line from that console and click ok 

Hi. This message means some lines were folded by a console, it is possible to hide them by turning off the console folding, but it would make console output ambiguous. https://www.jetbrains.com/help/idea/settings-console-folding.html