Add missing init calls in buffer tests in 1.0.1

These tests are asynchronous, but didn't call waitUntilDone correctly in
1.0.1 when run under the webkit test runner. Add the missing call. In
1.0.2+, waitUntilDone is called indirectly and no changes are needed.
Ensure that webkit test runner's notifyDone is called

Some tests include js-test-post.js directly instead of calling
finishTest. Make sure that these tests also call notifyDone in 1.0.2 and
newer versions of the test suite, since waitUntilDone is always called.
Merge pull request #372 from NVIDIA/buffer-test-init

Add missing init calls in buffer tests in 1.0.1
Merge pull request #371 from NVIDIA/notify-done-fix2

Ensure that webkit test runner's notifyDone is called