Are you storing your path along with the other variables in setenv.sh.file? How do you start the tomcat service? Are you using the distro installed tomcat or have you downloaded it from tomcat.apache.org?
It might be best to open a support ticket if it doesn't get resolved here soon -- for tracking purposes and to ensure we have a supporting article if needed.
Try creating a setenv.sh file (refer to this post Configuring Tomcat startup settings without GUI) with the following contents (please adjust the paths to jre and license accordingly):
# Java Options
"-Djava.awt.headless=true -Djava.net.preferIPv4Stack=true -Dserver -Dd64 -XX:+UseNUMA -XX:+UseConcMarkSweepGC -Dfile.encoding=UTF-8 -Djava.library.path=/usr/share/tomcat8/8.0.33/webapps/Thingworx/WEB-INF/extensions"
in addition to what Polina suggested it can be useful to execute ps -ef after starting tomcat but before it dies.
This would allow you to see the full java command that is actually started and you can then confirm if the expected -Djava.library.path is actualy loaded with the correct full path.
Hope this helps