bpo-35561: Supress valgrind false alarm on epoll_ctl(event) (GH-18060)

Update Misc/valgrind-python.supp to suppress the false alarm.
diff --git a/Misc/valgrind-python.supp b/Misc/valgrind-python.supp
index 38a5ea3..c9c45ba 100644
--- a/Misc/valgrind-python.supp
+++ b/Misc/valgrind-python.supp
@@ -264,6 +264,14 @@
 }
 
 {
+   Uninitialised byte(s) false alarm, see bpo-35561
+   Memcheck:Param
+   epoll_ctl(event)
+   fun:epoll_ctl
+   fun:pyepoll_internal_ctl
+}
+
+{
    ZLIB problems, see test_gzip
    Memcheck:Cond
    obj:/lib/libz.so.1.2.3