[Bug sanitizer/86022] TCB size calculated in ThreadDescriptorSize() is wrong for glibc-2.14

[marxin at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86022

--- Comment #3 from Martin Liška <marxin at gcc dot gnu.org> ---
I verified that it's really correct for glibc 2.14 on -m32. Let's see whether
upstream will approve the change.