RFR: 8283122: [AIX, s390] UnsafeCopyMemory 'Mismatched' Tests Fail on Big Endian Systems [v3]

[Tyler Steele]

> This is a testbug present on big endian systems. UnsafeCopyMemory.java contains a few tests with 'mismatched' source and destination size. These tests use Unsafe.copyMemory to copy 4 bytes between longs and ints. The location of the bytes to be copied (if the copy comes from a long), or the offset into which the bytes should be copied (if the copy is into a long) are different on big and little endian systems.
> 
> Copying from a long to int on a little endian system, the bytes to be copied are those present at the long's address.
> 
> 
> src: _ _ _ _ | _ _ _ _
>      ^ ~ ~ ^ LE copy
> dst: _ _ _ _
> 
> 
> On BE systems, the bytes are offset by 4.
> 
> 
> src: _ _ _ _ | _ _ _ _
>                ^ ~ ~ ^ BE copy
> dst: _ _ _ _
> 
> 
> The situation for copying into a long from an int is analogous.
> 
> This PR adds the required offset for the 'mismatched copy' tests. With this change, UnsafeCopyMemory.java now passes on AIX and s390.

Tyler Steele has updated the pull request incrementally with one additional commit since the last revision:

  Removes unneeded bug label

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/7811/files
  - new: https://git.openjdk.java.net/jdk/pull/7811/files/8a592c01..30e22822

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=7811&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=7811&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/7811.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/7811/head:pull/7811

PR: https://git.openjdk.java.net/jdk/pull/7811