ci: ensure that PHP is set up properly for Travis tests

.travis.yml

@@ -35,6 +35,10 @@ install:
 - node -v
 - npm install
 - composer install -o --prefer-dist --no-interaction
+before_script:
+- if php -v | grep -q 'Xdebug'; then phpenv config-rm xdebug.ini; fi
+- if [[ ${TRAVIS_PHP_VERSION:0:3} == "7.3" ]]; then pecl install pcov; fi
+- bash bin/install-wp-tests.sh wordpress_test root '' localhost $WP_VERSION
 script:
 - npm run install-build-tools
 - npm run test