title: ReactNative ListView inconsistent separator lines
body: <p>On Android 4.4, ListView separator lines are inconsistent in thickness, and some do not render. 
  I can't see how this can be a code issue, this is how I render them:</p>
  
  <pre><code>     separator: {
          height: 1,
          backgroundColor: 'grey',
        }
        ...
        &lt;ListView
        renderSeparator={(sectionID, rowID) =&gt;
          &lt;View key={`${sectionID}-${rowID}`} style={styles.separator} /&gt;
        }
        .../&gt;
  </code></pre>
  
  <p>Here is a screenshot of a View with this problem:</p>
  
  <p><a href="https://i.stack.imgur.com/aq2iG.png" rel="noreferrer"><img src="https://i.stack.imgur.com/aq2iG.png" alt="enter image description here"></a></p>
  
  <p>This issue does not happen on iOS or Android 6.</p>
  
  <p>Anyone had this problem before?</p>
  
  <p><strong>Update</strong></p>
  
  <p>I did a test, this is not Android4 issue. It happens on all API version when running on Nexus One device (in android emulator)</p>