patch 8.2.0858: not easy to require Lua modules

Problem:    Not easy to require Lua modules.
Solution:   Improve use of Lua path. (Prabir Shrestha, closes #6098)
diff --git a/Filelist b/Filelist
index 6cd442a..8bb0e2f 100644
--- a/Filelist
+++ b/Filelist
@@ -157,6 +157,7 @@
 		src/testdir/*.py \
 		src/testdir/lsan-suppress.txt \
 		src/testdir/sautest/autoload/*.vim \
+		src/testdir/testluaplugin/lua/testluaplugin/*.lua \
 		src/testdir/check.vim \
 		src/testdir/gui_init.vim \
 		src/testdir/gui_preinit.vim \