tests/tcg: Fix run for tests with specific plugin

tests/tcg: Fix run for tests with specific plugin

Commit 25aaf0cb7f (“tests/tcg: reduce the number of plugin test
combinations”) added support for running tests with specific plugins
passed via the EXTRA_RUNS variable.

However, due to the optimization, the rules generated as a shuffled
combination of tests and plugins might not cover the rules required to
run the tests with a specific plugin passed via EXTRA_RUNS.

This commit fixes it by correctly generating the rules for the tests
that require a specific plugin to run, which are now passed via the
EXTRA_RUNS_WITH_PLUGIN instead of via the EXTRA_RUNS variable.

The fix essentially excludes the tests passed via EXTRA_RUNS_WITH_PLUGIN
from the rules created by the shuffled combination of tests and plugins,
to avoid running the tests twice, and generates the rules for the
test/plugin combinations listed in the EXTRA_RUNS_WITH_PLUGIN variable.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Tested-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-id: 20250801001305.2352554-1-gustavo.romero@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>