patch 8.2.2105: sound test is a bit flaky

Problem:    Sound test is a bit flaky.
Solution:   Use WaitForAssert(). (Dominique Pellé, closes #7429)
diff --git a/src/version.c b/src/version.c
index 08594a5..28360de 100644
--- a/src/version.c
+++ b/src/version.c
@@ -751,6 +751,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    2105,
+/**/
     2104,
 /**/
     2103,