t1400: use consistent style for test_expect_success calls

Structure calls as

    test_expect_success 'description' '
    	body
    '

Use double quotes for the description if it requires parameter
expansion or contains a single quote.

Signed-off-by: Kyle Meyer <[email protected]>
Reviewed-by: Jeff King <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: kyleam