RFR(S) 8211336 [TESTBUG] appcds tests with incorrect usage of -XX:+UseStringDeduplication

[Ioi Lam]

http://cr.openjdk.java.net/~iklam/jdk12/8211336-cds-test-fix-for-string-dedup.v01/
https://bugs.openjdk.java.net/browse/JDK-8211336

Please review this small test fix:

These are "shell" tests that need to pass certain options (such as
-XX:+UseStringDeduplication) to child JVM processes that are launched via
jdk.test.lib.process.ProcessTools. The tests were using this:

    * @run main/othervm -XX:+UseStringDeduplication ExerciseGC

However, options passed this way are not passed by ProcessTools. The fix is
to change to the following

    * @run driver ExerciseGC -XX:+UseStringDeduplication

and let the main test program explicitly pass args[] (indirectly)
to ProcessTools.

(I also cleaned up some unnecessary @module tags)

Test in progress with hs-tier1/2.

Thanks
- Ioi