fix timezone core import in jest

Test Plan:
- tests pass
- brent is happy

Change-Id: I26c021bd50e2cf63aec96aedd987f6b8c6370c62
Reviewed-on: https://gerrit.instructure.com/173592
Reviewed-by: Brent Burgoyne <bburgoyne@instructure.com>
Tested-by: Jenkins
QA-Review: Steven Burnett <sburnett@instructure.com>
Product-Review: Steven Burnett <sburnett@instructure.com>

jest.config.js

@@ -20,7 +20,8 @@ module.exports = {
   moduleNameMapper: {
     '^i18n!(.*$)': '<rootDir>/jest/i18nTransformer.js',
     '^compiled/(.*)$': '<rootDir>/app/coffeescripts/$1',
-    '^jsx/(.*)$': '<rootDir>/app/jsx/$1'
+    '^jsx/(.*)$': '<rootDir>/app/jsx/$1',
+    "^timezone$": "<rootDir>/public/javascripts/timezone_core.js"
   },
   roots: ['app/jsx'],
   moduleDirectories: [
@@ -47,5 +48,5 @@ module.exports = {
   transform: {
     '^i18n': '<rootDir>/jest/i18nTransformer.js',
     '^.+\\.jsx?$': 'babel-jest'
-  }
+  },
 }