[8u] Request for Approval for backport of 8180048: Interned string and symbol table leak memory during parallel unlinking

[Thomas Schatzl]

Hi all,

  could you please approve the backport of JDK-8180048 to 8u-dev?

This fixes a serious memory leak in G1.

Bug: https://bugs.openjdk.java.net/browse/JDK-8180048
Webrev: http://cr.openjdk.java.net/~tschatzl/8180048-8u/webrev/
Review thread (8u): http://mail.openjdk.java.net/pipermail/hotspot-gc-d
ev/2017-May/019872.html
Original webrev (9): http://cr.openjdk.java.net/~tschatzl/8180048/webre
v.2/
Review thread (9): http://mail.openjdk.java.net/pipermail/hotspot-gc-de
v/2017-May/019855.html

Patch from 9 does not apply cleanly because of cleanup done in the
meantime (split of symbolTable.?pp into symbolTable/stringTable.?pp,
and removal of some code in 9).

Thanks,
  Thomas