[TEST]: ci: run only on 16 cores

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

Author: nashif

.github/workflows/twister.yaml

@@ -143,7 +143,7 @@ jobs:
       CCACHE_IGNOREOPTIONS: '-specs=* --specs=*'
       BSIM_OUT_PATH: /opt/bsim/
       BSIM_COMPONENTS_PATH: /opt/bsim/components
-      TWISTER_COMMON: ' --test-config tests/test_config_ci.yaml --no-detailed-test-id --force-color --inline-logs -v -N -M --retry-failed 3 --timeout-multiplier 2 '
+      TWISTER_COMMON: ' --test-config tests/test_config_ci.yaml --no-detailed-test-id --force-color --inline-logs -v -N -M --retry-failed 3 --timeout-multiplier 2 -j 16'
       WEEKLY_OPTIONS: ' -M --build-only --all --show-footprint --report-filtered'
       PR_OPTIONS: ' --clobber-output --integration'
       PUSH_OPTIONS: ' --clobber-output -M --show-footprint --report-filtered'