[Bug sanitizer/64265] [5 Regression] r217669 broke tsan

[dvyukov at google dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64265

--- Comment #13 from Dmitry Vyukov <dvyukov at google dot com> ---
> ... we actually don't want any __tsan_func_{entry,exit} calls if there are no memory accesses in the function...

... and no calls to other functions, because these functions can contain memory
accesses and tsan needs func_entry/exit to maintain stack traces.