patch 9.0.0372: MS-Windows: "%T" time format does not appear to work

Problem:    MS-Windows: "%T" time format does not appear to work.
Solution:   Use "%H:%M:%S" instead.
diff --git a/src/testdir/shared.vim b/src/testdir/shared.vim
index 72cf836..09d942f 100644
--- a/src/testdir/shared.vim
+++ b/src/testdir/shared.vim
@@ -101,7 +101,7 @@
     " Wait for some time for the port number to be there.
     let port = GetPort()
     if port == 0
-      call assert_report(strftime("%T") .. " Can't start " .. a:cmd)
+      call assert_report(strftime("%H:%M:%S") .. " Can't start " .. a:cmd)
       return
     endif