plugins: add explicit dependency in functional tests

plugins: add explicit dependency in functional tests

./tests/functional/test_aarch64_tcg_plugins.py needs to have plugin
libinsn built. However, it's not listed as a dependency, so meson can't
know it needs to be built.

Thus, we keep track of all plugins, and add them as an explicit
dependency.

Fixes: 4c134d07b9e ("tests: add a new set of tests to exercise plugins")
Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20250304222439.2035603-9-alex.bennee@linaro.org>