Revert "Added test for CustomEvent init SerializedScriptValue assert. This is a simple test of the initCustomEvent internal API to make sure that it can be called, and that after initialization, the detail getter can be successfully used." (r154153).

Seems to be causing random asserts in subsequent webkit_unit_tests.

TBR=jww,adamk,abarth

Review URL: https://codereview.chromium.org/18071010

git-svn-id: svn://svn.chromium.org/blink/trunk@154179 bbb929c8-8fbe-4397-9dbb-9b2b20218538