Remove stale platform-specific expectations

As the description says, this patch removes the stale platform-specific
expectation entries for tests that no longer exist (or have moved).

BUG=369287
TBR=ojan

Review URL: https://codereview.chromium.org/265843006

git-svn-id: svn://svn.chromium.org/blink/trunk@173189 bbb929c8-8fbe-4397-9dbb-9b2b20218538