[OMPT] Second chunk of final OMPT 5.0 interface updates

The omp-tools.h file is generated from the OpenMP spec to ensure that the interface
is implemented as specified.
The other changes are necessary to update the interface implementation to the
final version as published in 5.0.
The omp-tools.h header was previously called ompt.h, currently a copy under this name
is installed for legacy tools.

Patch partially perpared by @sconvent

Reviewers: AndreyChurbanov, hbae, Hahnfeld

Reviewed By: hbae

Tags: #openmp, #ompt

Differential Revision: https://reviews.llvm.org/D55579

llvm-svn: 351197