Check python variable

Author: winskuo-quic

.ci/scripts/test_qnn_static_llama.sh

@@ -7,6 +7,12 @@
 
 set -exu
 
+if [[ -z "${PYTHON_EXECUTABLE:-}" ]]; then
+  PYTHON_EXECUTABLE=python3
+fi
+
+which "${PYTHON_EXECUTABLE}"
+
 
 # Download and create artifacts.
 PARAMS="params.json"