reset: fix validation in sparse index test

Update t1092 test 'reset with pathspecs outside sparse definition' to verify
index contents. The use of `rev-parse` verifies the contents of HEAD, not
the index, providing no real validation of the reset results. Conversely,
`ls-files` reports the contents of the index (OIDs, flags, filenames), which
are then compared across checkouts to ensure compatible index states.

Fixes 741a2c9 (reset: expand test coverage for sparse checkouts,
2021-09-27).

Signed-off-by: Victoria Dye <[email protected]>
Reviewed-by: Elijah Newren <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: vdye

t/t1092-sparse-checkout-compatibility.sh

@@ -596,13 +596,11 @@ test_expect_success 'reset with pathspecs outside sparse definition' '
 
 	test_sparse_match git reset update-folder1 -- folder1 &&
 	git -C full-checkout reset update-folder1 -- folder1 &&
-	test_sparse_match git status --porcelain=v2 &&
-	test_all_match git rev-parse HEAD:folder1 &&
+	test_all_match git ls-files -s -- folder1 &&
 
 	test_sparse_match git reset update-folder2 -- folder2/a &&
 	git -C full-checkout reset update-folder2 -- folder2/a &&
-	test_sparse_match git status --porcelain=v2 &&
-	test_all_match git rev-parse HEAD:folder2/a
+	test_all_match git ls-files -s -- folder2/a
 '
 
 test_expect_success 'reset with wildcard pathspec' '