Remove LayoutTests/plugins/destroy-plugin-from-callback.html

Remove LayoutTests/plugins/destroy-plugin-from-callback.html

Remove test that claims to pass unless it crashes yet times out or fail
with a different output more often than not. Given that it was added to
catch a regression in the webkit plugin architecture that isn't used by
Blink anymore the test is rather pointless at this ponint.

R=adamk@chromium.org
BUG=503848
NOTRY=true

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=197764

[adamk, 2015-06-24 17:27:18]

lgtm

[eae, 2015-06-24 17:36:10]

The CQ bit was checked by eae@chromium.org

[commit-bot: I haz the power, 2015-06-24 17:36:39]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1207793002/1

[commit-bot: I haz the power, 2015-06-24 18:41:12]

Committed patchset #1 (id:1) as
https://src.chromium.org/viewvc/blink?view=rev&revision=197764