chore: update iOS unit test configuration (#1841)

Author: devversion

test/browser-providers.ts

@@ -43,11 +43,9 @@ const configuration: { [name: string]: ConfigurationInfo } = {
   'Safari7':      { unitTest: {target: null, required: false}, e2e: {target: null, required: true}},
   'Safari8':      { unitTest: {target: 'BS', required: false}, e2e: {target: null, required: true}},
   'Safari9':      { unitTest: {target: 'BS', required: false}, e2e: {target: null, required: true}},
-  'iOS7':         { unitTest: {target: 'BS', required: false}, e2e: {target: null, required: true}},
+  'iOS7':         { unitTest: {target: null, required: false}, e2e: {target: null, required: true}},
   'iOS8':         { unitTest: {target: 'BS', required: true}, e2e: {target: null, required: true}},
-  // TODO(mlaval): iOS9 deactivated as not reliable, reactivate after
-  //               https://github.com/angular/angular/issues/5408
-  'iOS9':         { unitTest: {target: 'BS', required: false}, e2e: {target: null, required: true}},
+  'iOS9':         { unitTest: {target: 'BS', required: true}, e2e: {target: null, required: true}},
   'WindowsPhone': { unitTest: {target: 'BS', required: false}, e2e: {target: null, required: true}}
 };