[webcrypto] Remove support for AES 192-bit keys (1 of 2)

[webcrypto] Remove support for AES 192-bit keys (1 of 2)

Removes uses of 192-bit AES keys from the LayoutTests. Since once the corresponding Chromium change lands they will no longer work.

BUG=381829
Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=176066

[jww, 2014-06-12 22:27:36]

lgtm

[eroman, 2014-06-12 22:43:37]

The CQ bit was checked by eroman@chromium.org

[commit-bot: I haz the power, 2014-06-12 22:44:00]

CQ is trying da patch. Follow status at
 https://chromium-status.appspot.com/cq/eroman@chromium.org/325323004/1

[commit-bot: I haz the power, 2014-06-12 23:19:19]

FYI, CQ is re-trying this CL (attempt #1).
The failing builders are:
  linux_blink_dbg on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/linux_blink_dbg/builds/1...)
  win_blink_rel on tryserver.blink
(http://build.chromium.org/p/tryserver.blink/builders/win_blink_rel/builds/11830)

[commit-bot: I haz the power, 2014-06-13 00:23:32]

Change committed as 176066