zbd/004: Check zone boundary writes using zones without zone capacity gap

zbd/004: Check zone boundary writes using zones without zone capacity gap

The test case zbd/004 checks zone boundary write handling by block layer
using two contiguous sequential write required zones. This test is valid
when the first zone has same zone capacity as zone size. However, if the
zone has zone capacity smaller than zone size, the write in the zone
beyond zone capacity limit causes write error and the test fails.

To avoid the write error, find the two zones with first zone that has
zone capacity same as zone size. If such zones are not found, skip the
test case.

Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>