This test relies on the width of the test font and the fallback font
being different to determine whether they matched or not. The
`offsetWidth` rounding change introduced in 51c7afdf5f caused these
widths to appear the same, meaning the test failed. This change avoids
the issue by using a longer string with a deliberately wide glyph.
Previously, FontFace objects created via the JS and added to
`document.fonts` were stored in the FontFaceSet but never participated
in font matching during style resolution. We now store both
CSS-connected and JS-created font faces in a unified map on
`FontComputer`, keyed by family name, and include them all as
candidates in the font matching algorithm.