[Bug sanitizer/64888] ubsan doesn't work with openmp

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64888

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
But these *.Lubsan_data0 are read-only I think, so I don't think there's a
problem if multiple threads read such a variable.