Remove deprecated and unused run_and_throw_if_fail from webkitpy

Remove deprecated and unused run_and_throw_if_fail from webkitpy

This function was used by build-webkit according to it's comment.
Currently it is used by FlakyTests and some unit tests but it can
be replaced with run_command

Committed: https://src.chromium.org/viewvc/blink?view=rev&revision=184157

[kkristof, 2014-10-21 08:13:06]

kkosztyo.u-szeged@partner.samsung.com changed reviewers:
+ abarth@chromium.org, dpranke@google.com, thakis@chromium.org

[Dirk Pranke, 2014-10-21 19:14:13]

dpranke@chromium.org changed reviewers:
+ dpranke@chromium.org

[Dirk Pranke, 2014-10-21 19:14:14]

lgtm

[kkristof, 2014-10-22 08:20:16]

The CQ bit was checked by kkosztyo.u-szeged@partner.samsung.com

[commit-bot: I haz the power, 2014-10-22 08:21:17]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/663023008/1

[commit-bot: I haz the power, 2014-10-22 09:36:42]

Committed patchset #1 (id:1) as 184157