[OpenMP] [OMPT] [6/8] Added callback support for target data operations,...

[OpenMP] [OMPT] [6/8] Added callback support for target data operations, target submit, and target regions.

This patch adds support for invoking target callbacks but does not yet
invoke them. A new structure OmptInterface has been added that tracks
thread local states including correlation ids. This structure defines
methods that will be called from the device independent target library
with information related to a target entry point for which a callback
is invoked. These methods in turn use the callback functions maintained
by OmptDeviceCallbacksTy to invoke the tool supplied callbacks.

Depends on D124652

Patch from John Mellor-Crummey <johnmc@rice.edu>
With contributions from:
Dhruva Chakrabarti <Dhruva.Chakrabarti@amd.com>

Differential Revision: https://reviews.llvm.org/D127365