[lworld+vector] RFR: Merge lworld [v2]

[Xiaohong Gong]

> This patch merges the latest `valhalla:lworld` to
>  `valhalla:lworld+vector` branch, together with following
>  main changes:
> 
> 1. Resolve conflicts mainly caused by the BACKOUT of
>  `VectorShuffle refactory` in jdk mainline [1].
> 2. Fix the class id issue for `SafePointScalarMergeNode` added by [JDK-8287061](https://bugs.openjdk.java.net/browse/JDK-8287061). This causes an jvm crash
>  when building the jdk image. `lworld` branch also
>  fixes it (see [2]), but it seems the id is not correctly
>  ordered.
> 
> [1] https://github.com/openjdk/jdk/pull/14629
> 
> [2] https://github.com/openjdk/valhalla/blob/lworld/src/hotspot/share/opto/node.hpp#L738

Xiaohong Gong has refreshed the contents of this pull request, and previous commits have been removed. The incremental views will show differences compared to the previous content of the PR. The pull request contains one new commit since the last revision:

  Merge lworld

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

Changes:
  - all: https://git.openjdk.org/valhalla/pull/921/files
  - new: https://git.openjdk.org/valhalla/pull/921/files/9890580d..6bf52e45

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=valhalla&pr=921&range=01
 - incr: https://webrevs.openjdk.org/?repo=valhalla&pr=921&range=00-01

  Stats: 0 lines in 0 files changed: 0 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/valhalla/pull/921.diff
  Fetch: git fetch https://git.openjdk.org/valhalla.git pull/921/head:pull/921

PR: https://git.openjdk.org/valhalla/pull/921