patch 9.0.0430: cannot use repeat() with a blob

Problem:    Cannot use repeat() with a blob.
Solution:   Implement blob repeat. (closes #11090)
diff --git a/src/typval.c b/src/typval.c
index 12a741e..95abe21 100644
--- a/src/typval.c
+++ b/src/typval.c
@@ -792,6 +792,24 @@
 }
 
 /*
+ * Give an error and return FAIL unless "args[idx]" is a string or a number
+ * or a list or a blob.
+ */
+    int
+check_for_string_or_number_or_list_or_blob_arg(typval_T *args, int idx)
+{
+    if (args[idx].v_type != VAR_STRING
+	    && args[idx].v_type != VAR_NUMBER
+	    && args[idx].v_type != VAR_LIST
+	    && args[idx].v_type != VAR_BLOB)
+    {
+	semsg(_(e_string_number_list_or_blob_required_for_argument_nr), idx + 1);
+	return FAIL;
+    }
+    return OK;
+}
+
+/*
  * Give an error and return FAIL unless "args[idx]" is a string or a list
  * or a dict.
  */