[trace][intelpt] Support system-wide tracing [6] - Break IntelPTCollector into smalle...

[trace][intelpt] Support system-wide tracing [6] - Break IntelPTCollector into smaller files and minor refactor

IntelPTCollector is very big and has 3 classes in it. It's actually cleaner if each one has its own file. This also gives more visibility to the developer about the different kinds of "tracers" that we have.

Besides that, I'm now restricting the creation of the BinaryData chunks to GetState() instead of having it in different places, which is not very clean, because the gdb-remote protocol should be as restricted as possible.

Differential Revision: https://reviews.llvm.org/D125047