chore(build): remove IE8 target from all test configs

BREAKING CHANGE: As communicated before, IE8 is no longer supported.

more info: http://blog.angularjs.org/2013/12/angularjs-13-new-release-approaches.html

karma-shared.conf.js

@@ -45,12 +45,6 @@ module.exports = function(config, specificOptions) {
         platform: 'OS X 10.9',
         version: '7'
       },
-      'SL_IE_8': {
-        base: 'SauceLabs',
-        browserName: 'internet explorer',
-        platform: 'Windows 7',
-        version: '8'
-      },
       'SL_IE_9': {
         base: 'SauceLabs',
         browserName: 'internet explorer',
@@ -88,13 +82,6 @@ module.exports = function(config, specificOptions) {
         os: 'Windows',
         os_version: '8'
       },
-      'BS_IE_8': {
-        base: 'BrowserStack',
-        browser: 'ie',
-        browser_version: '8.0',
-        os: 'Windows',
-        os_version: '7'
-      },
       'BS_IE_9': {
         base: 'BrowserStack',
         browser: 'ie',