tsan: allow usage of global vars with ctors in interceptors

We allow usage of global/per-thread data with non-trivial ctors/dtors
throughout tsan code base by placing all global/per-thread data into
Context/ThreadState and then explicitly constructing them with
placement new. This greatly simplifies code by restricting the
"linker initialized plague" to only these 2 objects.

Do the same for interceptors data.

This allows to use Vector instead of bunch of hand-written code in:
https://reviews.llvm.org/D39619

Reviewed in: https://reviews.llvm.org/D39721

llvm-svn: 317587