RFR: JMC-6534 String deduplication rule assumes only G1 has feature

[Jie Kang]

Hi,

Please review this update to the String Deduplication rule. It now
also checks for Shenandoah GC and the messages have been updated
appropriately. I would also like to request translation assistance for
said messages for Chinese and Japanese. Specifically:

StringDeduplicationRule_RESULT_LONG_DESCRIPTION
StringDeduplicationRule_RESULT_GC_LONG

Webrev:
http://cr.openjdk.java.net/~jkang/jmc-6534/webrev.01/
JIRA:
https://bugs.openjdk.java.net/browse/JMC-6534


Regards,