Fix fallback specialization in SequenceStorageNodes#RepeatNode

Author: steve-s

graalpython/com.oracle.graal.python/src/com/oracle/graal/python/builtins/objects/common/SequenceStorageNodes.java

@@ -2542,7 +2542,8 @@ SequenceStorage doGeneric(SequenceStorage s, int times,
                         @Cached("create()") LenNode lenNode) {
             try {
                 int len = lenNode.execute(s);
-                SequenceStorage repeated = createEmptyNode.execute(s, Math.multiplyExact(len, times), -1);
+                int newLen = Math.multiplyExact(len, times);
+                SequenceStorage repeated = createEmptyNode.execute(s, newLen, -1);
 
                 for (int i = 0; i < len; i++) {
                     setItemNode.execute(repeated, i, getGetItemNode().execute(s, i));
@@ -2555,6 +2556,7 @@ SequenceStorage doGeneric(SequenceStorage s, int times,
                     }
                 }
 
+                repeated.setNewLength(newLen);
                 return repeated;
             } catch (OutOfMemoryError | ArithmeticException e) {
                 outOfMemProfile.enter();