tsan: introduce LazyInitialize

We call non-inlinable Initialize from all interceptors/syscalls,
but most of the time runtime is already initialized and this just
introduces unnecessary overhead.
Add LazyInitialize that (1) inlinable, (2) does nothing if
.preinit_array is enabled (expected case on Linux).

Depends on D107071.

Reviewed By: melver

Differential Revision: https://reviews.llvm.org/D107072