RFR: 8142362: Lots of code duplication in Copy class [v2]

[Coleen Phillimore]

> Removed an unused assembly function on one platform (_Copy_conjoint_bytes), and consolidated the linux and bsd x86, and linux and bsd aarch64 copy code that was duplicated.  There's unfortunately now an #ifndef _WINDOWS in copy_x86.hpp and copy_aarch64.hpp, and I couldn't combine the duplicate copy_<arch>.S files because Windows doesn't have this file (and couldn't convince the build system to ignore the .S file for windows).
> I didn't think it was worth adding an os_cpu/posix_x86 and os_cpu/posix_aarch64 directory for this small bit of code.
> 
> There could be more consolidation but the platform differences are subtle.  This change just moves around code without poking this bear.
> 
> Tested with tier1 on Oracle platforms, build on linux-x86-open,linux-s390x-open,linux-arm32-debug,linux-ppc64le-debug and Zero (zero in progress).

Coleen Phillimore has updated the pull request incrementally with one additional commit since the last revision:

  Fix Windows aarch64

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/6984/files
  - new: https://git.openjdk.java.net/jdk/pull/6984/files/ced521f9..fe6984a5

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=6984&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=6984&range=00-01

  Stats: 4 lines in 1 file changed: 2 ins; 2 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/6984.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/6984/head:pull/6984

PR: https://git.openjdk.java.net/jdk/pull/6984