Enable "Run Query in New Tab" in SQL Lab (#1343)

* Enable "Clone to New Tab" btn in QueryHistoryTable

Method #1; doesn't feel very clean.

Going to attempt to reimplement using an action and changing state directly
through the reducer rather than creating a new QueryEditor object directly from
the QueryTable

* Move Clone Logic to Action

* Implement PR feedback

* Clean up reducer action; fix bug

Bug => Attempting to clone anything other than the most recent Query for a given
TabbedQueryEditor would throw an exception, because we depended on lastQueryId
to find the title of the QueryEditor to clone. Since you can only activate a
clone from the currently active tab, we can instead fetch the ID of the Editor
to copy the Title of from the tip of tabHistory.

* Tests for Reducer Action

* Fix CodeClimate feedback

caravel/assets/spec/javascripts/sqllab/reducers_spec.js

@@ -0,0 +1,28 @@
+import * as r from '../../../javascripts/SqlLab/reducers';
+import * as actions from '../../../javascripts/SqlLab/actions';
+import { describe, it } from 'mocha';
+import { expect } from 'chai';
+
+describe('sqlLabReducer', () => {
+  describe('CLONE_QUERY_TO_NEW_TAB', () => {
+    const testQuery = { sql: 'SELECT * FROM...', dbId: 1, id: 1 };
+    const state = Object.assign(r.initialState, { queries: [testQuery] });
+    const newState = r.sqlLabReducer(state, actions.cloneQueryToNewTab(testQuery));
+
+    it('should have at most one more tab', () => {
+      expect(newState.queryEditors).have.length(2);
+    });
+  
+    it('should have the same SQL as the cloned query', () => {
+      expect(newState.queryEditors[1].sql).to.equal(testQuery.sql);
+    });
+
+    it('should prefix the new tab title with "Copy of"', () => {
+      expect(newState.queryEditors[1].title).to.include('Copy of');
+    });
+
+    it('should push the cloned tab onto tab history stack', () => {
+      expect(newState.tabHistory[1]).to.eq(newState.queryEditors[1].id);
+    });
+  });
+});