t1092: add cherry-pick, rebase tests

Add tests to check that cherry-pick and rebase behave the same in the
sparse-index case as in the full index cases. These tests are agnostic
to GIT_TEST_MERGE_ALGORITHM, so a full CI test suite will check both the
'ort' and 'recursive' strategies on this test.

Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Reviewed-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/t1092-sparse-checkout-compatibility.sh

@@ -481,14 +481,17 @@ test_expect_success 'checkout and reset (mixed) [sparse]' '
 	test_sparse_match git reset update-folder2
 '
 
-test_expect_success 'merge' '
+test_expect_success 'merge, cherry-pick, and rebase' '
 	init_repos &&
 
-	test_all_match git checkout -b merge update-deep &&
-	test_all_match git merge -m "folder1" update-folder1 &&
-	test_all_match git rev-parse HEAD^{tree} &&
-	test_all_match git merge -m "folder2" update-folder2 &&
-	test_all_match git rev-parse HEAD^{tree}
+	for OPERATION in "merge -m merge" cherry-pick rebase
+	do
+		test_all_match git checkout -B temp update-deep &&
+		test_all_match git $OPERATION update-folder1 &&
+		test_all_match git rev-parse HEAD^{tree} &&
+		test_all_match git $OPERATION update-folder2 &&
+		test_all_match git rev-parse HEAD^{tree} || return 1
+	done
 '
 
 # NEEDSWORK: This test is documenting current behavior, but that