Remove a whitelist rescuing non-compliant WebSocket opening handshake.

http://src.chromium.org/viewvc/blink?view=rev&rev=159754 added a temporally
whitelist not to fail non-compliant servers in the WebSocket opening
handshake. Half a year has passed since then and it can be deleted now.

BUG=363598

Review URL: https://codereview.chromium.org/240083003

git-svn-id: svn://svn.chromium.org/blink/trunk@172022 bbb929c8-8fbe-4397-9dbb-9b2b20218538