Fix workspace cleanup in tests. (#4169)

tests/mocha/block_test.js

@@ -1234,6 +1234,7 @@ suite('Blocks', function() {
     });
     teardown(function() {
       Blockly.Events.enable();
+      workspaceTeardown.call(this, this.workspace);
       delete Blockly.Blocks['variable_block'];
     });
     suite('Connecting and Disconnecting', function() {

tests/mocha/event_test.js

@@ -660,7 +660,7 @@ suite('Events', function() {
         // Expect the workspace to not have a variable with ID 'test_block_id'.
         chai.assert.isNull(this.workspace.getVariableById(TEST_BLOCK_ID));
       } finally {
-        workspaceSvg.dispose();
+        workspaceTeardown.call(this, workspaceSvg);
       }
     });
 

tests/mocha/field_test.js

@@ -392,7 +392,7 @@ suite('Abstract Fields', function() {
           this.workspace.createDom();
         });
         teardown(function() {
-          this.workspace = null;
+          workspaceTeardown.call(this, this.workspace);
         });
         test('Before Append', function() {
           Blockly.Blocks['tooltip'] = {

tests/mocha/xml_procedures_test.js

@@ -38,7 +38,7 @@ suite('Procedures XML', function() {
       };
     });
     teardown(function() {
-      this.workspace.dispose();
+      workspaceTeardown.call(this, this.workspace);
     });
 
     suite('Definition Blocks', function() {