hide javac warnings about unused AutoCloseable

com.oracle.truffle.r.engine/src/com/oracle/truffle/r/engine/TruffleRLanguage.java

@@ -121,6 +121,7 @@ public final class TruffleRLanguage extends TruffleLanguage<RContext> {
     }
 
     @Override
+    @SuppressWarnings("try")
     protected CallTarget parse(Source source, Node context, String... argumentNames) throws IOException {
         try (Closeable c = RContext.withinContext(findContext(createFindContextNode()))) {
             try {

com.oracle.truffle.r.engine/src/com/oracle/truffle/r/engine/interop/RInteropExecuteNode.java

@@ -62,6 +62,7 @@ class RInteropExecuteNode extends RootNode {
     }
 
     @Override
+    @SuppressWarnings("try")
     public Object execute(VirtualFrame frame) {
         RFunction function = (RFunction) ForeignAccess.getReceiver(frame);
         List<Object> arguments = ForeignAccess.getArguments(frame);