test: remove extra polyfills only for testing (#2428)

Removes the testing polyfills by using jasmine and not jest in the
browser. We were already using jasmine but where overriding those
methods with jest versions which was not needed.

The previous karma setup also used a single entrypoint which meant that
not all integration tests were running because all files were not
imported in integrations/index.ts.

This also eliminates 79 dev dependencies.