stash: move sparse index test for stash -u

Move the test for `git stash -u` into the `sparse-index is not expanded` test
because it no longer expands the index (temporary or otherwise) when all
stashed files are in the sparse checkout definition.

Signed-off-by: Victoria Dye <vdye@github.com>

t/t1092-sparse-checkout-compatibility.sh

@@ -1234,6 +1234,9 @@ test_expect_success 'sparse-index is not expanded' '
 	ensure_not_expanded stash apply stash@{0} &&
 	ensure_not_expanded stash drop stash@{0} &&
 
+	ensure_not_expanded stash -u &&
+	ensure_not_expanded stash pop &&
+
 	ensure_not_expanded stash create &&
 	oid=$(git -C sparse-index stash create) &&
 	ensure_not_expanded stash store -m "test" $oid &&
@@ -1383,28 +1386,6 @@ test_expect_success 'sparse index is not expanded: read-tree' '
 	ensure_not_expanded read-tree --prefix=deep/deeper2 -u deepest
 '
 
-# NEEDSWORK: although the full repository's index is _not_ expanded as part of
-# stash, a temporary index, which is _not_ sparse, is created when stashing and
-# applying a stash of untracked files. As a result, the test reports that it
-# finds an instance of `ensure_full_index`, but it does not carry with it the
-# performance implications of expanding the full repository index.
-test_expect_success 'sparse index is not expanded: stash -u' '
-	init_repos &&
-
-	mkdir -p sparse-index/folder1 &&
-	echo >>sparse-index/README.md &&
-	echo >>sparse-index/a &&
-	echo >>sparse-index/folder1/new &&
-
-	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
-		git -C sparse-index stash -u &&
-	test_region index ensure_full_index trace2.txt &&
-
-	GIT_TRACE2_EVENT="$(pwd)/trace2.txt" GIT_TRACE2_EVENT_NESTING=10 \
-		git -C sparse-index stash pop &&
-	test_region index ensure_full_index trace2.txt
-'
-
 # NEEDSWORK: similar to `git add`, untracked files outside of the sparse
 # checkout definition are successfully stashed and unstashed.
 test_expect_success 'stash -u outside sparse checkout definition' '