fix: resolve relative paths in emulator smoke test scripts

[immanuwell]

Tiny shell paper cut fix.

These smoke-test helpers call sibling scripts with ./..., so from repo root they blow up with No such file or directory before the emulator checks even start. Kinda annoying, pretty easy fix tho.

Repro:

bash ./test-latest.sh
bash ./debian_component_based/test-components.sh

This patch resolves helper paths from each script's own directory, so the same commands work from repo root and from inside the subdirs too. Low risk, just path plumbing really.

Checked:

• bash -n on the touched scripts
• mocked runs of both helper chains from repo root
• mocked run of emulators/test-all-emulators.sh from inside emulators/

Related context: #506, #593