remove WPT <to-javascript-parent-initiated-parent-csp-disallow.html>.
It tests the same aspects like
https://searchfox.org/mozilla-central/rev/ec342a3d481d9ac3324d1041e05eefa6b61392d2/testing/web-platform/tests/content-security-policy/navigation/to-javascript-parent-initiated-parent-csp.html.
Namely: a source CSP which forbids executing javascript:-URLs and a
target CSP which allows executing javascript:-URLs.
That scenario was also intended to be tested when the test was added
(see #14358).
Differential Revision: https://phabricator.services.mozilla.com/D226328
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1926037
gecko-commit: e75d49ab2ffec27226a791f9956b4c9aa04a6327
gecko-reviewers: tschuster