Bug 29862: Add missing txn begin/rollback in TestBuilder.t

Bug 29862: Add missing txn begin/rollback in TestBuilder.t

It fixes the tests when SearchEngine=ES
 t/db_dependent/TestBuilder.t .. 7/15 Invalid MARC field expression: l5ffglZ_upqqcwOvaiyALgXfyJw2Ot2AGRPUsiAPzSFHfd8J_hsnuQ8z75B8RKc_kyo2rFBp8BrPNwcM1FPhc01ngP01HU_Z7Rx1VHfcIcmrifYnjBDWNmYB9N5_4xEnxMH7ZhqC9b2Bz9wf9
 wSEmx64x6t5xFFKX at /kohadevbox/koha/C4/Biblio.pm line 306.
     # Looks like you planned 12 tests but ran 6.

 #   Failed test 'Tests for delete method'
 #   at t/db_dependent/TestBuilder.t line 302.
 Can't call method "biblionumber" on an undefined value at t/db_dependent/TestBuilder.t line 281.
 # Looks like your test exited with 11 just after 8.

Previous subtest created invalid date in the ES mappings.

Test plan:
Set SearchEngine=ES and run the tests, they must pass.

Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>