For me, the following tests always fail, both at work and home: fast/forms/text-control-intrinsic-widths.html fast/text/backslash-to-yen-sign-dynamic.html fast/text/backslash-to-yen-sign-euc.html fast/text/backslash-to-yen-sign.html fast/text/international/bidi-mirror-he-ar.html fast/text/ipa-tone-letters.html In most cases, I think this is because I have MS fonts installed (e.g. MS Gothic).
See also: bug 6400, bug 35273.
*** This bug has been marked as a duplicate of bug 35273 ***