[lldb][intel-pt] Remove old plugin

[wallace]

Summary

Now that LLDB proper has built-in support for intel-pt traces, we can remove the old plugin written by Intel. It has less features and it's hard to work with.

As a test, I ran "ninja lldbIntelFeatures" and it worked.

[clayborg]

I would be ok with this. Can you track down the original author and add them to the review of this to be sure they aren't using it anymore, and if they need tracing that they have everything they need with your new functionality?

[wallace]

I'll contact them again. Last time I did they didn't reply. And btw, this feature was broken for years and last year i revived this plugin, so I imagine no one was using it. And in terms of features, the new implementation supports the same features

[wallace]

Btw, lldb-server for a few months hasn't been supporting the functionalities required by the old plugin, and as no one has complained, I imagine it's been not actively used.