Dictionary fixes, corrected TestIndexWriterUnicode test

73 failures in the last TC test run with dictionary lookups in Lucene42DocValuesProducer and LiveFieldValues, PR contains fixes for those.

TestIndexWriterUnicode.TestAllUnicodeChars was failing, looks like a mistake in porting, corrected based on Java branch (https://github.com/apache/lucene-solr/blob/lucene_solr_4_8_0/lucene/core/src/test/org/apache/lucene/index/TestIndexWriterUnicode.java#L221)