leak tests: mark all checkout-index tests as passing with SANITIZE=leak

Mark some tests that match "*{checkout,switch}*" as passing when git
is compiled with SANITIZE=leak. They'll now be listed as running under
the "GIT_TEST_PASSING_SANITIZE_LEAK=true" test mode (the "linux-leaks"
CI target).

Unfortunately almost all of those tests fail when compiled with
SANITIZE=leak, these only pass because they run "checkout-index", not
the main "checkout" command.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/t/t2002-checkout-cache-u.sh b/t/t2002-checkout-cache-u.sh
index 70361c8..fc95cf9 100755
--- a/t/t2002-checkout-cache-u.sh
+++ b/t/t2002-checkout-cache-u.sh
@@ -8,6 +8,7 @@
 With -u flag, git checkout-index internally runs the equivalent of
 git update-index --refresh on the checked out entry.'
 
+TEST_PASSES_SANITIZE_LEAK=true
 . ./test-lib.sh
 
 test_expect_success \