This patch adds zero-parameter overloads for `DumpFrameTree()` and
`DumpFrameTreeInCSSPixels()`, making it easier to call these functions in the
debugger without having to pass `false` as an argument.
Additionally, this patch reverts bug 1959538 since that change [1] is no longer
needed with these new overloads.
[1]https://hg.mozilla.org/mozilla-central/rev/7371d5813735
Differential Revision: https://phabricator.services.mozilla.com/D245155