Analyzers: apply required changes to use the Analyzer framework and adapt to new Solr classloading
Fix tests: CompressionTest
Document.getFieldable is now getField (and returns a different type)

Also, Field no longer implements Fieldable
Update tests: ProvidedIdTest
Searcher instances no longer require to be closed (and close() method was removed)

Needless to say, you still need to close the IndexReader which was provided to the Searchers.
[SPI] We changed the createTimeoutException() API
Fix StoreNormsTest: Field#getOmitNorms method is gone
Fix test WorkDoneOnEntitiesTest
More IndexReader open replaced
Fix test: SharingBufferIndexProviderTest
[API] SortField type is now an inner enum SortField.Type.STRING
Reintroduce as deprecated the addNumericFieldToDocument helper, fix NumericField tests
Reuse our EMPTY_DOCIDSET implementation in tests
Update DocIdSet tests and add one for the Elias-Fano encoder
Fix test: SortTest
Fix tests: FilterTest