Only run browser tests if we have secure vars

Hopefully will be resolved by
https://github.com/travis-ci/travis-core/pull/418

browser-tests/run.sh

 #!/bin/bash
 
-npm i && \
-eval "npm test -- $@"
+args="$@"
 
+run_tests ()
+{
+	npm i && \
+	eval "npm test -- $args"
+}
+
+if [ "$TRAVIS_PULL_REQUEST" == "true" ] && [ "$TRAVIS_SECURE_ENV_VARS" == "true" ]
+then
+	run_tests
+elif [ "$TRAVIS_PULL_REQUEST" == "true" ] && [ "$TRAVIS_SECURE_ENV_VARS" == "false" ]
+then
+	exit 0
+else
+	run_tests
+fi