LUCENE-1285: WeightedSpanTermExtractor incorrectly treats the same terms occurring in different query types

Files:
modified: /lucene/java/trunk/contrib/highlighter/src/test/org/apache/lucene/search/highlight/HighlighterTest.java (try)
modified: /lucene/java/trunk/contrib/highlighter/src/java/org/apache/lucene/search/highlight/WeightedSpanTermExtractor.java (try)