[css-flex] Remove flexbox's specific computePreferredLogicalWidths()
Created attachment 408850 [details] Patch
Created attachment 408912 [details] Patch
I was removing too much code. The one in RenderBlock is ankward but we should leave it untouched until it isn't properly fixed in flexbox.
Committed r267183: <https://trac.webkit.org/changeset/267183>
<rdar://problem/69049162>