tests/tcg: remove ADDITIONAL_PLUGINS_TESTS

We never actually used this is the end. Remove it to enable
re-factoring.

Fixes: 7cefff22d54 (tests/tcg: add mechanism to run specific tests with plugins)
Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-ID: <20250725154517.3523095-9-alex.bennee@linaro.org>
1 file changed