Support importing trace-cmd binary output (text works)

It would be great if perfetto would support importing trace data from trace-cmd. This would make it much easier to do ad-hoc tracing during embedded kernel development on Linux. trace-cmd supports wildcards and simple command lines so quick changes in the tracing are simple.

The issue requests importing trace-cmd binary output, while noting that text output already works. Start by locating the existing trace-cmd text import path and studying the binary format and expected import behavior. Done means trace-cmd binary data imports successfully without breaking text import.

Written by the indexing model from the issue text.