RFR: Fix negative index OOB exception in string dedup stress test

[Roman Kennke]

Noooooooooooooooooooo. Wtf!

Plesse push it!
Roman


Am 18. Oktober 2018 02:09:28 MESZ schrieb Zhengyu Gu <zgu at redhat.com>:
>It is indeed the result of Math.abs(Integer.MIN_VALUE) = 
>Integer.MIN_VALUE, which is a negative value (-2147483648).
>
>Webrev: 
>http://cr.openjdk.java.net/~zgu/shenandoah/dedup_neg_index/webrev.00/
>
>Test:
>   With following script.
>
>for i in {0..50}
>do
>${JAVA_HOME}/bin/java -Xmx512M -XX:+UnlockExperimentalVMOptions 
>-XX:+UseShenandoahGC -XX:+UnlockDiagnosticVMOptions 
>-XX:ShenandoahGCHeuristics=passive  -XX:-ShenandoahDegeneratedGC 
>-XX:+UseStringDeduplication -D
>targetOverwrites=40000000 ShenandoahStrDedupStress
>done
>
>
>Thanks,
>
>-Zhengyu