Use page-table presence checks in checker link stores

The checker's link-store wrappers answered Has by calling TryGet, so
presence checks still resolved arena indexes even though the paged
store can answer from the page entry alone. Route them to the store
presence checks so checker queries get the cheaper path.

Author: jakebailey

tsc/internal/checker/links.go

@@ -28,7 +28,11 @@ func (s *nodeLinkStore[V]) Get(node *ast.Node) *V {
 }
 
 func (s *nodeLinkStore[V]) Has(node *ast.Node) bool {
-	return s.TryGet(node) != nil
+	id := uint64(s.gen.GetNodeId(node))
+	if id >= ast.BlockIdOffset && id < ast.BlockIdOffset+maxPageLinkCount {
+		return s.pages.Has(id - ast.BlockIdOffset)
+	}
+	return s.links.Has(id)
 }
 
 func (s *nodeLinkStore[V]) TryGet(node *ast.Node) *V {
@@ -54,7 +58,11 @@ func (s *symbolLinkStore[V]) Get(symbol *ast.Symbol) *V {
 }
 
 func (s *symbolLinkStore[V]) Has(symbol *ast.Symbol) bool {
-	return s.TryGet(symbol) != nil
+	id := uint64(s.gen.GetSymbolId(symbol))
+	if id >= ast.BlockIdOffset && id < ast.BlockIdOffset+maxPageLinkCount {
+		return s.pages.Has(id - ast.BlockIdOffset)
+	}
+	return s.links.Has(id)
 }
 
 func (s *symbolLinkStore[V]) TryGet(symbol *ast.Symbol) *V {