[lworld+vector] Integrated: Merge lworld

[Jatin Bhateja]

Merge from lworld in lworld+vector branch.

Apart from the usual merge conflict resolution, the patch also contains bug fixes for some special handling around multifields.
To segregate the code changes and maintain the history[1][2][3][4][5], these bug fixes were initially checked into a temporary private merge branch and are now part of the merge. 


[1] Special copy constructor used for initializing base and synthetic multifields 
    https://github.com/jatin-bhateja/valhalla/commit/0fe3153e79251fe661ea1bd368472f2f75cb360d
[2] Fix ciField population for multifields 
    https://github.com/jatin-bhateja/valhalla/commit/4a26aff14801e010ea238e8d5a52a52465c6f849
[3] Multifield handling during type domain buildup
     https://github.com/jatin-bhateja/valhalla/commit/74ca0245c5d9f5eb186baa962e11d3f5c8f4ed35
[4] prevent store forwarding across CPU memory barrier
     https://github.com/jatin-bhateja/valhalla/commit/cfc71acd89b2e3233d788565f1cf1061651a70f9
[5] Fix to accommodate additional padding during offset computation of multifields
     https://github.com/jatin-bhateja/valhalla/commit/75ec6296531839ab375efa58b909827269994449

After latest merge, all the VectorAPI and Valhalla JTREG tests are passing with -XX:-UseNonAtomicValueFlattening at
variaous AVX levels. With -XX:+UseNonAtomicValueFlattening there are some failures which will be addressed post
merge commit.

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

Commit messages:
 - FIXME for MULTIFILE handling in acmp map
 - Merge branch 'lworld' of http://github.com/openjdk/valhalla into merge_lworld2
 - Merge branch 'lworld' of http://github.com/openjdk/valhalla into merge_lworld2
 - Merge branch 'lworld' of https://github.com/openjdk/valhalla into merge_lworld2
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - Merge lworld
 - JDK 8327435: [lworld+vector] Align existing Vector API support with JEP 401
 - ... and 18 more: https://git.openjdk.org/valhalla/compare/a07dfe93...802d8f79

The merge commit only contains trivial merges, so no merge-specific webrevs have been generated.

Changes: https://git.openjdk.org/valhalla/pull/1688/files
  Stats: 12464 lines in 288 files changed: 5054 ins; 2474 del; 4936 mod
  Patch: https://git.openjdk.org/valhalla/pull/1688.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/1688/head:pull/1688

PR: https://git.openjdk.org/valhalla/pull/1688