COF throws NPE if mtl is not specified

The following valid template stopped working once we switched from Javatest 4.3b20 to Javatest 4.4b10:

> <JAVA> -cp <javatest.jar> com.sun.javatest.cof.Main -ts <JCK-runtime-7> -o report.cof -xsd <JCK_WORKDIR>

Now the following NPE is thrown and an empty report.cof is generated:

Exception in thread "main" java.lang.NullPointerException
        at com.sun.javatest.cof.COFTest.checkLostTestCases(COFTest.java:253)
        at com.sun.javatest.cof.COFTest.<init>(COFTest.java:181)
        at com.sun.javatest.cof.COFTestSuite.write(COFTestSuite.java:141)
        at com.sun.javatest.cof.COFItem.writeCollection(COFItem.java:165)
        at com.sun.javatest.cof.COFItem.write(COFItem.java:141)
        at com.sun.javatest.cof.COFTestSuites.write(COFTestSuites.java:123)
        at com.sun.javatest.cof.COFItem.write(COFItem.java:138)
        at com.sun.javatest.cof.Main.run(Main.java:315)
        at com.sun.javatest.cof.Main.main(Main.java:149)


Specifying a new argument '-mtl' helps.