Randoop: add runner parameter for filtering out tests that do not call SUT

[micskeiz]

Randoop generated tests for snippets in L2 where the test code just creates complex strings, but does not call the snippet method.

For example, this is the code for one of the tests:

    byte[] byte_array0 = new byte[] {  };
    // The following exception was thrown during execution in test generation
    try {
      java.lang.String str4 = new java.lang.String(byte_array0, 100, 100, "");
      org.junit.Assert.fail("Expected exception of type java.lang.StringIndexOutOfBoundsException");
    } catch (java.lang.StringIndexOutOfBoundsException e) {
      // Expected exception.
      if (! e.getClass().getCanonicalName().equals("java.lang.StringIndexOutOfBoundsException")) {
        org.junit.Assert.fail("Expected exception of type java.lang.StringIndexOutOfBoundsException, got " + e.getClass().getCanonicalName());
      }
    }       
    // Regression assertion (captures the current behavior of the code)
    org.junit.Assert.assertNotNull(byte_array0);

Randoop has a parameter to handle this:

--include-if-classname-appears=regex. Classes, one of which every test must use. Randoop will only output tests that have at least one use of a member of a class whose name matches the regular expression.

Add this parameter to Randoop runner to filter out these tests.