revert(3p/git): Revert merge of git upstream at v2.26.2

This causes cgit to serve error pages, which is undesirable.

This reverts commit 5229c9b232, reversing
changes made to f2b211131f.

third_party/git/t/t2022-checkout-paths.sh

@@ -78,15 +78,4 @@ test_expect_success 'do not touch files that are already up-to-date' '
 	test_cmp expect actual
 '
 
-test_expect_success 'checkout HEAD adds deleted intent-to-add file back to index' '
-	echo "nonempty" >nonempty &&
-	>empty &&
-	git add nonempty empty &&
-	git commit -m "create files to be deleted" &&
-	git rm --cached nonempty empty &&
-	git add -N nonempty empty &&
-	git checkout HEAD nonempty empty &&
-	git diff --cached --exit-code
-'
-
 test_done