[lworld] RFR: 8371604: [lworld] SIGSEGV in InlineKlass::is_payload_marked_as_null [v2]

[Paul Hübner]

> Hi all,
> 
> This patch fixes several `int` overflows relating to flat array element loads/stores. 
> I've included some gtests that address a subset of these changes.  We should test flat arrays larger than 16GB in size, which is not something we can feasibly do in our tier1 jtreg tests. I've filed [JDK-8372261](https://bugs.openjdk.org/browse/JDK-8372261) as a follow-up RFE to investigate this.
> 
> Testing: tiers 1-4, [`LocalityCheck.java`](https://bugs.openjdk.org/secure/attachment/117136/LocalityCheck.java) run locally 100 times.

Paul Hübner has updated the pull request incrementally with one additional commit since the last revision:

  C1 changes

-------------

Changes:
  - all: https://git.openjdk.org/valhalla/pull/1752/files
  - new: https://git.openjdk.org/valhalla/pull/1752/files/a7dbd59f..49320b90

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=1752&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=1752&range=00-01

  Stats: 9 lines in 4 files changed: 1 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/valhalla/pull/1752.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1752/head:pull/1752

PR: https://git.openjdk.org/valhalla/pull/1752