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DnD changes ported from ladybird introduced several regressions
in DataFlavor.selectBestTextFlavor():

1.DataFlavor.selectBestTextFlavor(null) returned null.
  Now it throws NullPointerException.
2.DataFlavor.selectBestTextFlavor(new DataFlavor[0]) returned null.
  Now it throws NoSuchElementException.
3.DataFlavor.selectBestTextFlavor() is documented to return a flavor
  in a supported encoding.
  Now it can return a flavor in an unsupported encoding.
  It is possible if the passed array contains a single text flavor
  in an unsupported encoding for example.
  
Here is the test case to reproduce the problem:
====================================================================
import java.awt.datatransfer.DataFlavor;

public class Test {
    public static void main(String[] args) {
        try {
            DataFlavor flavor = DataFlavor.selectBestTextFlavor(null);
            System.out.println("best1=" + flavor);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        try {
            DataFlavor flavor = DataFlavor.selectBestTextFlavor(new DataFlavor[0]);
            System.out.println("best2=" + flavor);
        } catch (Throwable e) {
            e.printStackTrace();
        }
        try {
            DataFlavor flavor =
                DataFlavor.selectBestTextFlavor(new DataFlavor[]
                                                { new DataFlavor("text/plain; charset=unsupported; class=java.io.InputStream") });
            System.out.println("best3=" + flavor);
        } catch (Throwable e) {
            e.printStackTrace();
        }
    }
}
==================================================================

Here is the output indicating the buggy behavior
in the current merlin workspace:
==================================================================
java.lang.NullPointerException
        at java.util.Arrays$ArrayList.<init>(Arrays.java:2239)
        at java.util.Arrays.asList(Arrays.java:2225)
        at java.awt.datatransfer.DataFlavor.selectBestTextFlavor(DataFlavor.java:475)
        at Test.main(Test.java:6)
java.util.NoSuchElementException
        at java.util.AbstractList$Itr.next(AbstractList.java:423)
        at java.util.Collections.max(Collections.java:646)
        at java.awt.datatransfer.DataFlavor.selectBestTextFlavor(DataFlavor.java:475)
        at Test.main(Test.java:12)
best3=java.awt.datatransfer.DataFlavor[representationclass=java.io.InputStream;mimetype=text/plain]
==================================================================
Here is the output produced by merlin build b39:
==================================================================
best1=null
best2=null
best3=null
==================================================================