Call StartRemoveFrame() before calling ContinueRemoveFrame() in nsBlockFrame::RemoveFloat().
After Bug 1903141 Part 3 [1], StartRemoveFrame() does not get called when there
is no float list. We need to make sure StartRemoveFrame() is called before
calling ContinueRemoveFrame().
[1] https://hg.mozilla.org/mozilla-central/rev/c2ba52894016007c3f5c4f21241f14d3cd7bd7a3
Differential Revision: https://phabricator.services.mozilla.com/D214775
bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1904409
gecko-commit: 82e42849ba9214a0b3aaefdcec0615638a231b02
gecko-reviewers: dholbert