The following classes deriving from nsBlockFrame always set
NS_BLOCK_STATIC_BFC in their constructors or initializers:
- nsComboboxControlFrame
- nsFileControlFrame
- nsSelectsAreaFrame
- ColumnSetWrapperFrame
- nsMathMLmathBlockFrame
Do that in nsBlockFrame::Init instead. Behavior is unchanged.
Differential Revision: https://phabricator.services.mozilla.com/D199097