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/t7415-submodule-names.sh

@@ -191,61 +191,4 @@ test_expect_success 'fsck detects corrupt .gitmodules' '
 	)
 '
 
-test_expect_success MINGW 'prevent git~1 squatting on Windows' '
-	git init squatting &&
-	(
-		cd squatting &&
-		mkdir a &&
-		touch a/..git &&
-		git add a/..git &&
-		test_tick &&
-		git commit -m initial &&
-
-		modules="$(test_write_lines \
-			"[submodule \"b.\"]" "url = ." "path = c" \
-			"[submodule \"b\"]" "url = ." "path = d\\\\a" |
-			git hash-object -w --stdin)" &&
-		rev="$(git rev-parse --verify HEAD)" &&
-		hash="$(echo x | git hash-object -w --stdin)" &&
-		test_must_fail git update-index --add \
-			--cacheinfo 160000,$rev,d\\a 2>err &&
-		test_i18ngrep "Invalid path" err &&
-		git -c core.protectNTFS=false update-index --add \
-			--cacheinfo 100644,$modules,.gitmodules \
-			--cacheinfo 160000,$rev,c \
-			--cacheinfo 160000,$rev,d\\a \
-			--cacheinfo 100644,$hash,d./a/x \
-			--cacheinfo 100644,$hash,d./a/..git &&
-		test_tick &&
-		git -c core.protectNTFS=false commit -m "module"
-	) &&
-	test_must_fail git -c core.protectNTFS=false \
-		clone --recurse-submodules squatting squatting-clone 2>err &&
-	test_i18ngrep -e "directory not empty" -e "not an empty directory" err &&
-	! grep gitdir squatting-clone/d/a/git~2
-'
-
-test_expect_success 'git dirs of sibling submodules must not be nested' '
-	git init nested &&
-	test_commit -C nested nested &&
-	(
-		cd nested &&
-		cat >.gitmodules <<-EOF &&
-		[submodule "hippo"]
-			url = .
-			path = thing1
-		[submodule "hippo/hooks"]
-			url = .
-			path = thing2
-		EOF
-		git clone . thing1 &&
-		git clone . thing2 &&
-		git add .gitmodules thing1 thing2 &&
-		test_tick &&
-		git commit -m nested
-	) &&
-	test_must_fail git clone --recurse-submodules nested clone 2>err &&
-	test_i18ngrep "is inside git dir" err
-'
-
 test_done