Make text-autospace-001 platform independent (#47668)
The current test relies on Blink's implementation detail:
- Test considers that spacing is always added as a leading space
to the glyph's advance, which will influence on the results we
get while calculating the advances on the test.
We can make this a ref test such that it just matters that the added
space is between the relevant adjacent glyphs. It won't matter if
it is added as a trailing or leading space.