How can I remove the Visualforce page label in lightning component?

If you are really that desperate to get rid of the label why not embed the VF page inside a Lightning component and embed the lightning component inside the object page instead of using the visualforce component.

<aura:component implements="force:appHostable,flexipage:availableForAllPageTypes,flexipage:availableForRecordHome,force:hasRecordId,force:lightningQuickAction" access="global" >
    <iframe src="{!'https://praowin-dev-ed--c.gus.visual.force.com/apex/testpage?Id=' + v.recordId }" width="100%" height="100%" frameBorder="0"/>
</aura:component>

VF embedded as iframe inside a lightning component:

It took a little trial and error, but I was able to solve it by using the "No-Break Space" unicode character (U+00A0) as the Visualforce lightning component title.