MAGETWO-56556: [GITHUB PR#3779] Add dispatching of view_block_abstract_to_html_after event

- fix Unit tests

Author: vkorotun

lib/internal/Magento/Framework/View/Element/AbstractBlock.php

@@ -676,7 +676,10 @@ public function toHtml()
                 'html' => $html,
             ]
         );
-        $this->_eventManager->dispatch('view_block_abstract_to_html_after', ['block' => $this, 'transport' => $transportObject]);
+        $this->_eventManager->dispatch('view_block_abstract_to_html_after', [
+            'block' => $this,
+            'transport' => $transportObject
+        ]);
         $html = $transportObject->getHtml();
 
         return $html;

lib/internal/Magento/Framework/View/Test/Unit/Element/AbstractBlockTest.php

@@ -204,7 +204,7 @@ public function testToHtmlWhenModuleIsDisabled()
         $moduleName = 'Test';
         $this->block->setData('module_name', $moduleName);
 
-        $this->eventManagerMock->expects($this->once())
+        $this->eventManagerMock->expects($this->exactly(2))
             ->method('dispatch')
             ->with('view_block_abstract_to_html_before', ['block' => $this->block]);
         $this->scopeConfigMock->expects($this->once())
@@ -239,7 +239,7 @@ public function testGetCacheLifetimeViaToHtml(
         $this->block->setData('module_name', $moduleName);
         $this->block->setData('cache_lifetime', $cacheLifetime);
 
-        $this->eventManagerMock->expects($this->once())
+        $this->eventManagerMock->expects($this->exactly(2))
             ->method('dispatch')
             ->with('view_block_abstract_to_html_before', ['block' => $this->block]);
         $this->scopeConfigMock->expects($this->once())