Which in itself was effectively a revert of
3364fefe

Keeping the old broken line height calculation code is just masking of
the real problem; there are some code elsewhere that have fragile
workarounds to the real bug here (the removed code here shows a good
example of such workarounds). On Mac we use the correct metrics as well,
so we need to find the quirks and fix them, instead of pretending they
do not exist.

This fixes fdo#55469, among others.

Change-Id: I36f13b28eaba022b7c388feae7e0bfd0ed1c3e89