8197531: Miscellaneous changes imported from jsr166 CVS 2018-04

Reviewed-by: martin, psandoz

src/java.base/share/classes/java/util/concurrent/Exchanger.java

@@ -641,7 +641,7 @@ public class Exchanger<V> {
             MATCH = l.findVarHandle(Node.class, "match", Object.class);
             AA = MethodHandles.arrayElementVarHandle(Node[].class);
         } catch (ReflectiveOperationException e) {
-            throw new Error(e);
+            throw new ExceptionInInitializerError(e);
         }
     }