Revert "WebCrypto: Add SHA-1 support to crypto.subtle.digest()."

This reverts r154310 to see if it was responsible for layout test flake on buildbots.

BUG=245025

Review URL: https://codereview.chromium.org/19401003

git-svn-id: svn://svn.chromium.org/blink/trunk@154318 bbb929c8-8fbe-4397-9dbb-9b2b20218538