hexagon: make vmem and buffer-size configurable (#22487)

* hexagon: allow host to set max vmem size

We use a sane default but it's helpful to allow for an override if needed.

* hexagon: add support for measuring vmem space and move pinned mmaping management to host

* hexagon: update vmem checks to use uint64

* hexagon: bump op buffers to 16 (matches max mmaps)

* hexagon: bump default vmem to 3.2GB

* hexagon: add support for autodetecting vmem space and some logging cleanup in that area

* hexagon: fix whitespace warnings

* Update scripts/snapdragon/adb/run-cli.sh

Co-authored-by: Pascal <admin@serveurperso.com>

* hex-adb: fix run-completion script

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Co-authored-by: Pascal <admin@serveurperso.com>