8211792: Fix misplaced BarrierSet forward declarations

Reviewed-by: shade, zgu

src/hotspot/share/interpreter/templateTable.hpp

@@ -36,6 +36,7 @@
 // and the snippet generator, a template is assigned to each bytecode which can be
 // used to generate the bytecode's implementation if needed.
 
+class BarrierSet;
 class InterpreterMacroAssembler;
 
 // A Template describes the properties of a code template for a given bytecode

src/hotspot/share/oops/oop.hpp

@@ -46,7 +46,6 @@ class OopClosure;
 class ScanClosure;
 class FastScanClosure;
 class FilteringClosure;
-class BarrierSet;
 class CMSIsAliveClosure;
 
 class PSPromotionManager;