Feature: Faster BMP -> BMDA communications

[dragonmux]

Detailed description

After having a couple of conversations with ALTracer about the speed and performance of BMDA interacting with the firmware, we realised that the current 1-byte-at-a-time solution for reads, while correct, is extremely far from performant but there's a simple solution to the problem that doesn't sacrifice correctness - slipping a large buffer in between the reads and the reading.

This PR addresses this by adding a 4KiB buffer in between the probe reads and BMDA's platform_buffer_read() on both Linux/macOS and Windows. This significantly reduces the number of syscalls being made and streamlines the data transport through BMDA from the probe. A reasonable speedup on current firmware was observed with no drawbacks.

Your checklist for this pull request

• I've read the Code of Conduct
• I've read the guidelines for contributing to this repository
• It builds for hardware native (make PROBE_HOST=native)
• It builds as BMDA (make PROBE_HOST=hosted)
• I've tested it to the best of my ability
• My commit messages provide a useful short description of what the commits do

Closing issues

[esden]

LGTM