Renames existing nsFrameLoader::OwnerIsBrowser* methods to add "Moz" prefix for
clarity.
Adds nsFrameLoader::OwnerIsIsolatedMozBrowserFrame which checks the noisolation
attribute of mozbrowser frames, if present.
This is used to set isolation in nsFrameLoader::GetNewTabContext only when true.
MozReview-Commit-ID: Dz02xBoKh1P