Remove h/t/incremental/frame-focus-before-load.html from SlowTests

As the test is not slow on recent runs, remove the entry from SlowTests.

BUG=601726
NOTRY=true

Review-Url: https://codereview.chromium.org/2172543002
Cr-Commit-Position: refs/heads/master@{#407053}
1 file changed