Add IntegrationTestCase::_getBodyAsString()
Add IntegrationTestCase::_getBodyAsString()

Refs: https://github.com/cakephp/cakephp/pull/9836#discussion_r90849991

mvdriel/cakephp,ADmad/cakephp,ADmad/cakephp,ndm2/cakephp,petteyg/cakephp,berrygoudswaard/cakephp,berrygoudswaard/cakephp,davidyell/cakephp,cakephp/cakephp,garethellis36/cakephp,dakota/cakephp,dakota/cakephp,petteyg/cakephp,tenkoma/cakephp,cakephp/cakephp,berrygoudswaard/cakephp,petteyg/cakephp,tenkoma/cakephp,ADmad/cakephp,CakeDC/cakephp,mvdriel/cakephp,garethellis36/cakephp,dakota/cakephp,mvdriel/cakephp,davidyell/cakephp,garethellis36/cakephp,ndm2/cakephp,cakephp/cakephp,garethellis36/cakephp,tenkoma/cakephp,cakephp/cakephp,dakota/cakephp,mvdriel/cakephp,petteyg/cakephp,davidyell/cakephp,ndm2/cakephp,CakeDC/cakephp,CakeDC/cakephp,CakeDC/cakephp,tenkoma/cakephp,ndm2/cakephp,ADmad/cakephp