fix jni fastpath GetitemI for object storage with primitive contents

Author: timfel

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/cext/hpy/GraalHPyContext.java

@@ -1621,6 +1621,11 @@ public final long ctxGetItemi(long hCollection, long lidx) {
                     return GraalHPyBoxing.boxHandle(createHandle(lresult).getId(this, ConditionProfile.getUncached()));
                 } else if (storage instanceof ObjectSequenceStorage) {
                     Object result = ((ObjectSequenceStorage) storage).getItemNormalized(idx);
+                    if (result instanceof Integer) {
+                        return GraalHPyBoxing.boxInt((int) result);
+                    } else if (result instanceof Double) {
+                        return GraalHPyBoxing.boxDouble((double) result);
+                    }
                     return GraalHPyBoxing.boxHandle(createHandle(result).getId(this, ConditionProfile.getUncached()));
                 }
                 // TODO: other storages...