Data races over function pointer initialization

[The check](https://github.com/intel/ittapi/blob/master/include/ittnotify.h#L243) of a function pointer can be performed concurrently with [initialization phase](https://github.com/intel/ittapi/blob/master/src/ittnotify/ittnotify_static.c#L1472) of function pointers. It is not a big deal for x86 but we need to suppress (https://github.com/oneapi-src/oneTBB/pull/659) Thread Sanitizer reports. Moreover, C/C++ does not state that pointers are atomic and considers such accesses as data races.