Fast JTAG profile sampler for ESP32/ESP32-S2 (OCD-1100)

[bryghtlabs-richard]

I implemented a non-intrusive program-counter sampler for ESP32-S3 in this patch, and it was a bit over 1000x faster than the current approach. In this thread, ESP-Sprite mentioned that this approach should work for the other xtensa chips, but I don't expect to get around to it for a while.

Please consider this a low priority request if anyone is interested to switch ESP32 and ESP32-S2 to the new sampler. For esp32_target and esp32s2_target, each just needs .profiling = esp_xtensa_profiling, assigned to switch over to the esp-xtensa non-intrusive sampler already in use by ESP32-S3, then a profile collected and analyzed.

[erhankur]

@bryghtlabs-richard, thank you for your contributions. We’ll certainly consider adding the new sampler to the ESP32 and ESP32-S2 targets.

[rsaxvc]

Verified original ESP32 works with non-intrusive sampler: https://review.openocd.org/c/openocd/+/8910