build: update jasmine for improved type safety (#8350)

* Bumps the version of Jasmine to allow for better type safety in the assertions.
* Fixes a few new compilation errors.

package.json

@@ -50,7 +50,7 @@
     "@types/glob": "^5.0.33",
     "@types/gulp": "3.8.32",
     "@types/hammerjs": "^2.0.35",
-    "@types/jasmine": "2.5.45",
+    "@types/jasmine": "^2.6.0",
     "@types/merge2": "^0.3.30",
     "@types/minimist": "^1.2.0",
     "@types/node": "^7.0.21",
@@ -87,7 +87,7 @@
     "highlight.js": "^9.11.0",
     "http-rewrite-middleware": "^0.1.6",
     "image-diff": "^1.6.3",
-    "jasmine-core": "^2.6.2",
+    "jasmine-core": "^2.8.0",
     "jsonwebtoken": "^7.4.1",
     "karma": "^1.7.1",
     "karma-browserstack-launcher": "^1.3.0",