- to allow jdt.ls to use the new SemanticHighlighting core
  classes, change the getPositionCategory() method to
  be public for both SemanticHighlightingPresenter
  and SemanticHighlightingPresentedCore
- have NLSHintHelperTest use SharedASTProviderCore instead
  of SharedASTProvider which is deprecated

Change-Id: Ie81fb5c4c74bd06d8adc08fe77370cbdd503096e
Signed-off-by: Jeff Johnston <jjohnstn@redhat.com>