ext4: introduce EXPORT_SYMBOL_FOR_EXT4_TEST() helper

ext4: introduce EXPORT_SYMBOL_FOR_EXT4_TEST() helper

[ Upstream commit 49504a512587147dd6da3b4b08832ccc157b97dc ]

Introduce EXPORT_SYMBOL_FOR_EXT4_TEST() helper for kuint test.

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://patch.msgid.link/20260314075258.1317579-2-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Stable-dep-of: 519b76ac0b31 ("ext4: fix mballoc-test.c is not compiled when EXT4_KUNIT_TESTS=M")
Signed-off-by: Sasha Levin <sashal@kernel.org>