patch 8.2.1389: file missing from the distribution

Problem:    File missing from the distribution.
Solution:   Add script_util.vim to the list of distributes files.
diff --git a/Filelist b/Filelist
index ecc1dd2..cc90c4d 100644
--- a/Filelist
+++ b/Filelist
@@ -172,6 +172,7 @@
 		src/testdir/setup_gui.vim \
 		src/testdir/shared.vim \
 		src/testdir/vim9.vim \
+		src/testdir/script_util.vim \
 		src/testdir/summarize.vim \
 		src/testdir/term_util.vim \
 		src/testdir/view_util.vim \