Remove Provider-specific logic

Author: Oleksandr Poliakov

evergreen/run-mongodb-oidc-tests.sh

@@ -60,7 +60,6 @@ popd
 # Assume "mongodb+srv" protocol
 export MONGODB_URI="mongodb+srv://${ADMIN_USER}:${ADMIN_PASSWORD}@${MONGODB_URI}?authSource=admin"
 export AWS_WEB_IDENTITY_TOKEN_FILE="$OIDC_TOKEN_DIR/test_user1"
-export OIDC_PROVIDER_NAME="aws"
 export OIDC_TESTS_ENABLED="true"
 
 if [ "Windows_NT" = "$OS" ]; then