[Tsan] Data race detection in mutex_init_and_lock

Because the global __itt__global is initialized in a critical section ([here](https://github.com/intel/ittapi/blob/69dd04030d3a2cf4c32e649ac1f2a628d5af6b46/src/ittnotify/ittnotify_static.c#L128)), Clang Thread Sanitizer flags it as a race condition.
We stumbled upon it by calling itt_string_create in a parallel section.

It is not critical, but it forces users to suppress those warnings. Maybe separating the initialization from the lock, and statically initializing the mutex would avoid this issue.