vim-patch.sh: improve performance with -l [ci skip] #10165

Down to < 1s now also (without get_vim_sources).

scripts/vim-patch.sh

@@ -425,8 +425,13 @@ show_vimpatches() {
     fi
   done
 }
+
+# Prints a human-formatted list of Vim commits, with instructional messages.
+show_vimpatches() {
+  get_vim_sources
+  printf "\nVim patches missing from Neovim:\n"
 
-# Prints a human-formatted list of Vim commits, with instructional messages.
+  local -A runtime_commits
   for commit in $(git -C "${VIM_SOURCE_DIR}" log --format="%H %D" -- runtime | sed 's/,\? tag: / /g'); do
     runtime_commits[$commit]=1
   done