vim-patch.sh: improve performance #10137

`vim-patch.sh -L`: down to ~0.5s from ~85s.
`vim-patch.sh -l`: down to ~6s from ~90s.

    % diff old new:
    193c193
    <   • v8.0.1366
    ---
    >   • v8.0.1367
    354d353
    <   • v8.0.1738

This is due to duplicate tags for Vim commits
(https://github.com/vim/vim/issues/4510):

  - vim/vim@1ad022a9b: tagged as v8.0.1367, v8.0.1366
  - vim/vim@5d69da462: tagged as v8.0.1739, v8.0.1738

scripts/vim-patch.sh

@@ -382,12 +382,21 @@ list_vimpatch_numbers() {
   list_vimpatch_tokens | while read -r vimpatch_token; do
     echo "$vimpatch_token" | grep '8\.0\.' | sed 's/.*vim-patch:8\.0\.\([0-9a-z]\+\).*/\1/'
   done
+}
 
 # Prints a newline-delimited list of Vim commits, for use by scripts.
 list_missing_vimpatches() {
   local token vim_commit vim_tag patch_number
   declare -A tokens
   declare -A vim_commit_tags
+
+  # Find all "vim-patch:xxx" tokens in the Nvim git log.
+  for token in $(list_vimpatch_tokens); do
+    tokens[$token]=1
+  done
+
+  # Create an associative array mapping Vim commits to tags.
+  eval "declare -A vim_commit_tags=(
     $(git -C "${VIM_SOURCE_DIR}" for-each-ref refs/tags \
       --format '[%(objectname)]=%(refname:lstrip=2)' \
       --sort='-*authordate' \
@@ -396,7 +405,8 @@ list_missing_vimpatches() {
 
   # Get missing Vim commits
   for vim_commit in $(list_vim_commits); do
-    # Check for vim-patch:<commit_hash> (usually runtime updates).
+    # Check for vim-patch:<commit_hash> (usually runtime updates).
+    token="vim-patch:${vim_commit:0:7}"
     if [[ "${tokens[$token]-}" ]]; then
       continue
     fi